Eastern State Penitentiary, located at 21st Street and Fairmount Avenue, was designed by British-born architect John Haviland. The prison, a technological marvel, took 14 years to complete, and featured central heating, flush toilets and showers in each cell. Even the new White House did not have such luxuries. The technology was not there for comfort, but to enable the complete isolation of each prisoner. Prisoners were to be rehabilitated through reflection on their crimes and spiritual enlightenment.

Julian Francis Abele led the Horace Trumbauer Company team of architects that designed the Central Library, constructed between 1917 and 1927. Abele was born in Philadelphia in 1881 and was the first African American graduate of the University of Pennsylvania Graduate School of fine Arts.

The Smith Memorial Arch in West Fairmount Park. In 1897 Richard Smith proposed this project to honor Pennsylvania's Civil War heroes and provided $500,000 for its construction. Architect James H. Windrim designed the monument and supervised construction. The Fairmount Park Association chose the 13 artists whose sculptures decorate the monument. The memorial was completed in 1912.

A "gentlemen's agreement" kept all of Philadelphia's buildings lower than the top of Alexander Milne Calder's statue of Penn on top of City Hall. However, in 1987 the "gentlemen's agreement" was broken when Mayor Wilson Goode endorsed the building of One Liberty Place.

The building at 19th and Vine Streets, setback from Logan Square, was designed by Horace Trumbauer's architectural firm, and opened on June 2, 1927.

Until 1987, a "gentlemen's agreement" prevented any Center City Philadelphia building from rising above the statue of William Penn. In that year, Mayor W. Wilson Goode endorsed the development of One Liberty Place, which broke the barrier.

Comcast Technology Center, 1122 feet; Comcast Center, 974 feet; One Liberty Place, 945 feet; Two Liberty Place, 846 feet; Mellon Bank Center, 791 feet; Three Logan, 738 feet; FMC Tower at Cira Centre South, 732 feet.

The Mellon Bank Center, located at 1735 Market Street, was designed by Kohn Pedersen Fox and completed in 1990.

The Curtis Center, located on 6th Street between Walnut and Sansom, was designed by Edgar V. Seeler and completed in 1907. The Curtis Center was once the Curtis Building which was the home of the Saturday Evening Post, Ladies Home Journal and other popular  magazines.

The Philadelphia Saving Fund Society (PSFS), the oldest savings bank in the US, built the first American skyscraper in the International style at 12th and Market in Philadelphia. This radical building was designed by George Howe and William Lescaze, and constructed between 1930 and 1932 during the Great Depression. It was the first American skyscraper built with glass-walled floors wrapping around a steel skeleton, and the first to be fully air conditioned. After PSFS's demise in 1992 the building was sold. It reopened in 2000 as the Loew's Hotel.

One Liberty Place was designed by Helmut Jahn, a Chicago based architect, in 1987. The 61 story, 958 foot tower at 17th and Chestnut Streets was the tallest in the city until the Comcast Center opened in 2008.

It was named the Everson Building after James Elverson, Jr., the publisher of the Inquirer. The Beaux Arts building, completed in 1925, is on the U.S. National Register of Historical Places.

The 16th century Japanese House with garden, designed by Junzo Yoshimura, was a gift made to the Fairmount Park Art Association by the America Japan Society in 1958. It was built in Nagoya, Japan, using traditional materials and techniques and reconstructed on the site of the first Japanese garden in North America, built for the1876 Centennial Exhibition.

The "Castle" is the upriver clubhouse of the Undine Barge Club. Frank Furness designed both the clubhouse and the boathouse (#13 Boathouse Row). The clubhouse was built in 1875 at a cost of $1700. It was named after the home of Prince Huldbrand in the Legend of Undine.

It is a large federal style house built in 1798 by William Lewis, who named it Summerhill. The second owner, Joseph Hemphill, added the two Greek Revival wings around 1828. Strawberry Mansion got its name in the 1850's when the farmers who owned it served strawberries and cream to the public. Strawberry Mansion was donated to the Fairmount Park Commission in 1871 by George Crock.

They are stairways without any visible means of support. There are 4 such 6-story tall stairways in the corners of City Hall in Philadelphia. The steps are cantilevered from the wall, with weight resting on the step below.

It was built between 1919 and 1937. Like the ancient Greek temples it emulates, its walls are slightly convex, as are the 72 steps of the stairway at its front.

The facade of the Central Library resembles the Gabriel Palaces on Place de la Concorde in Paris.

The original building 20th Street and the Parkway was designed by W.R. Morton Keast of the John T. Windrim firm.

The Academy moved to Logan Square in 1876, making it one of the older buildings on the Square.

The building cost $543,000; $370,000 was raised by Jasper Claghorn, $33,000 was a bequest from Henry Gilpin, $140,000 was raised by the sale of property, and the rest came from smaller donations.

On 20 acres between Frankford Creek and the Delaware River, the Arsenal was first activated in 1816 as a depot for ammunition. By 1840 it was involved in producing and developing ordinance. In 1977 it shut down and became a business center.

This large structure, which was built from 1846-64, is based on the Lombard Church of St. Charles. Napoleon Le Brun and George Notman designed it, putting a vaulted ceiling 80 feet above the seating capacity for 2,000.

First building erected in the United States for public use under the authority of the federal government was the structure for the U.S. Mint located at 7th Street near Arch in Philadelphia. It was established by the Act of April 2, 1792.

The oldest unaltered Lutheran Church in the United States is the Augustus Lutheran Church in Trappe, Pennsylvania. It was built in 1743.

Founded as a literary society and library in 1814, the Athenaeum moved into its present John Notman-designed Italianate Renaissance Revival building in 1947. It is one of the last remaining subscription libraries in the country.

The Second National Bank of the United States, which was designed by William Strickland, has a facade based on the Parthenon. It still stands at 420 Chestnut Street.

Cliveden is a mansion, built in 1761 by Benjamin Chew, at 6401 Germantown Avenue. It was at the epicenter of the Battle of Germantown during the Revolutionary War. It is now owned by the National Trust for Historic Preservation.

Thomas Jefferson was living at Graff House, at 7th and Market Streets in Philadelphia, when he wrote the first draft of the Declaration.

The mansion was built for the family of Samuel Wetherill in 1906. Frank Miles Day was the architect. In 1925 it became the home of the Art Alliance.

St. Patrick's Roman Catholic Church on 20th and Locust Streets in Philadelphia has for a cornerstone a rock from Armagh, Ireland, from which St. Patrick is said to have preached. It was reported that 30,000 people attenede the laying of the cornerstone by the bishop of Armagh.

Independence Hall, formerly known as the State House, was originally designed by Andrew Hamilton. Hamilton worked in collaboration with Edmund Wooley, a member of the Carpenter's Company, until Hamilton's death. The State House was conceived as a five-part plan based on the Palladian principle of two secondary buildings linked to a main block by arcades.

The Second Bank of the United States was designed by William Strickland. In 1818 he won the competition for the design of the building. The design of the two porticoes of the Second Bank of the United States is taken from the Parthenon in Greece. The Second Bank of the United States is located at 420 Chestnut Street, and was built from 1818 to 1824.

Carpenters' Hall was built by the Carpenters' Company. The Carpenters' Company of the City and County of Philadelphia was a group of master builders that joined together in 1774. The Hall is a part of Independence National Historic Park because the First Continental Congress met there in 1774. The building was mainly designed by Robert Smith, a respected member of the Company, and it was built from 1770-1774. It is located at 320 Chestnut Street between 3rd and 4th Streets.

The four oldest historically significant buildings in Philadelphia are the Wyck, built in 1690; the Wynnestay, built in 1690 or earlier; the Gloria Dei Church, built in 1700; and the Rittenhouse House, built in 1707 and part of Rittenhouse Town.

Wynnestay is located at 5125 Woodbine Avenue. It was built in 1689 on the property of Dr. Thomas Wynne, William Penn's personal physician and speaker of the Provincial Assembly in 1683.

Christ Church, which stands on 2nd just north of Market Street, was built between 1727 and 1754. Benjamin Franklin organized lotteries to provide funds for its completion. It is now a National Shrine.

The alley itself, originally known as Gilbert's Alley, was created in 1706. Landowners Arthur Wells and John Gilbert combined their properties to create a cart path to the river. Most of the original homes still remain occupied today.

The Bourse, between 4th and 5th on Ludlow and Ranstead Sts, was constructed in 1893-5 in imitation of European stock-exchanges.

Thomas Walters designed these Greek Revival structures in 1831-33. It was the first time such grand design, with porticos supported by marble Ionic columns, was applied to row houses.

It was built in 1744 as a summer house by John Wister, an immigrant from Germany in 1727 who had made money as a wine merchant. The stones and joists for the house are from the Wister property. British General James Agnew occupied the house during the Battle of Germantown. He was wounded and died in the front parlor.

The original portion of the house known as the Wyck Mansion was built in 1690 and is the oldest structure in Germantown. In 1771 it was replaced by the stone structure at the rear of the current house. In 1824 William Strickland was hired to remodel the house. Wick House is located at 6026 Germantown Avenue on the southwest corner of Walnut Lane.

The top of William Penn's hat on top of City Hall is 548 feet above street level. The William Penn statue is thirty-seven feet tall.

The Philadelphia Convention Center from Arch to Race Street and 11th to 13th street was opened in 1993 with 440,000 square feet of exhibit space. It was expanded to Broad Street in 2011 and now is over 2 million square feet.

City Hall was designed by John McArthur Jr., at Scottish architect. It was designed in the Second Empire Style, modeled after the Palais des Tuileries and the Louvre in Paris. The building took 30 years to build and was completed in 1901.

The Arts and Industries Building was built for this purpose and some proceeds from the exposition were used to build it.

It was naturalist John Bartram's, started in Philadelphia in about 1728. Bartram traveled from New England to Florida collecting seeds and plants for cultivation and exchange with English botanists. He was named Royal Botanist in America by King George III. His house and the garden,  at 54th Street and Lindbergh Blvd., are open to the public

The architect for the Academy of Music was Philadelphia-born Napoleon LeBrun, the son of a French diplomat. For acoustical purposes, the auditorium is designed after the Teatro alla Scala in Milan, Italy. The Renaissance Revival Style building was faced with brick, rather than marble, as a cost-saving measure.

It was the Merchant Exchange Building at 3rd and Walnut Streets. The building's impressive Greek Revival facade was designed by William Strickland. The Exchange was housed there from 1834 till 1876, then from 1902 till 1911.

Formed in 1862, the Union League of Philadelphia was one of the first of many Union Leagues organized across the North to support the government of the United States and the suppression of rebellion. In addition to raising money and troops, the Union League of Philadelphia produced 4.5 million copies of 145 pro-Union pamphlets and distributed them throughout the North. After the war's end the Union League supported black civil rights and spearheaded a successful campaign for streetcar desegregation in Philadelphia. In 1865 it moved into its present location at Broad and Sansom Streets.

The Mud Fort, located on the Delaware River just below the mouth of the Schuylkill, was originally built by the British but was garrisoned by the Americans at the beginning of the Revolutionary War. In 1777 the British reduced the fort to rubble. It was rebuilt after the war to protect the new nation's capital and was named after General Thomas Mifflin of Philadelphia.

It was repaired in 1863 and used as a military prison for Confederate prisoners of war, Union soldiers and civilians. Fort Mifflin was used as a US Navy ammunition depot during both world wars. The decommissioned fort has been restored and is open to the public.

Washington and his family lived in the Deshler-Morris House during the fall of 1793 and the summer of 1794. Washington and his cabinet met there and conducted the nation's business, leading to it's nickname, "the Germantown White House." The house, located at 5442 Germantown Avenue, was built in 1752 and enlarged in 1772. It has been restored and is open to the public.

It is the house occupied by Poe in 1943 before his move to New York. He lived in the house for about a year with his wife, Virginia and his mother-in-law. It is now a museum open to the public, located at 532 N. 7th Street, between Spring Garden and Green Streets.

This would mean a compact three-story house, with one room per story, which was built in the 18th, 19th or early 20th century.

Besides Carpenters’ Hall, Robert Smith designed the Christ Church steeple, St. Peter’s Church located at 3rd and Pine Streets and Old Pine Presbyterian Church at 4th and Pine.

It was the PSFS Building, designed by George Howe and William Lecaze, and then constructed by the Philadelphia Saving Fund Society in 1932. Standing at 12th and Market Streets, it rose 36-stories high, and was topped by a lighted sign reading PSFS.

That would be Cliveden, a mansion built in the 1760's by Benjamin Chew.  The British seized the mansion as headquarters for the British during the Battle of Germantown. It was was later restored by Blair McClenachan, who hosted Washington in 1787. The Chew family repurchased the house in 1797 and entertained Lafayette there in 1825. Cliveden is now a museum open to the public.

Frank Furness designed: Pennsylvania Academy of the Fine Arts at Broad and Cherry Streets; Centennial National Bank  (now the paul Peck Alumni Center, Drexel University)  at 32nd and Market St; Graver's Lane Station; Undine Barge Club boathouse on Kelly Drive; and the Fisher Fine Arts Library  of the University of Pennsylvania at 34th and Woodland Avenue.

Memorial Hall was the art gallery of the Centennial Exhibition of 1876, and it is one of the few buildings from the Exposition that still stand in Fairmount Park. One of America's first Beaux Arts buildings, it stands as a monument to the celebration of the nation's industrial achievements in the first one hundred years.

Frederick Graff designed and built the first stage of the Fairmount Water Works between 1812 and 1815. This design used steam engines to pump water from the river to the reservoir. In 1819 Graff built both the machinery and mill house, which bypassed the steam engines and used waterwheels to power the pumps.

The Sparks Shot Tower was built to fill a need for lead shot created by the 1807 Embargo Act and was the first such tower erected in the US. In 1808 it began manufacturing lead shot for sporting purposes, and during the war of 1812 began supplying the military with lead shot. Molten lead was poured through screens at the top of the tower.The size of the holes in the screen determined the callibre of the shot. As the drops of hot lead fell they cooled and hardened into pellets. They went through the final cooling process in vats of water at the base of the tower. When the shot was cooled it was then screened, polished, sorted, and packed in the main building.

The Moore College of Art was founded by Sara Worthington Pepter in 1848. In 1959 the College moved to its present location on Logan Square and 20th Street in Philadelphia.

"The Monastery", built circa 1747, was originally the home of Joseph Gorgas who was a member of the 7th day Baptist community in Ephrata. Brothers and sisters from Ephrata often stayed with him, which is probably why the house is referred to as a monastery. It is now a part of Fairmount Park, located at 1000 Kitchens Lane.

The model is housed in the Please Touch Museum, which is in the original Memorial Hall in Fairmount Park.

President Franklin Pierce attended the groundbreaking on June 18, 1855 and the completed building opened with a grand ball on January 26, 1857. The first performance was the opera, Il Travatore, performed on February 25, 1857. The Academy of Music is the oldest opera house still in use in the U.S. and was also the home of the Philadelphia Orchestra from 1900 to 2001.