Philadelphia (pronounced /ˌfɪləˈdɛlfiə/) is the largest city in Pennsylvania and the sixth-most-populous city in the United States.

In 2005, the population of the city proper was estimated to be over 1.4 million, while the Greater Philadelphia metropolitan area's population of 5.8 million made it the country's fifth-largest. The city is the nation's fourth-largest urban area by population, its fourth-largest consumer media market as ranked by the Nielsen Media Research, and the world's 49th-most-populous city. It is the county seat of Philadelphia County (with which it is coterminous). Popular nicknames for Philadelphia include Philly and The City of Brotherly Love (from Greek: Φιλαδέλφεια, [pʰi.la.ˈdel.pʰeː.a], Modern Greek: [fi.la'ðɛl.fi.a], "brotherly love" from philos-φίλος, "love", and adelphos-αδερφός or αδελφός "brother").

A commercial, educational, and cultural center, the city was once the second-largest in the British Empire (after London), and the social and geographical center of the original 13 American colonies. Ben Franklin took a large role in Philadelphia's early rise to prominence. It was in this city that many of the ideas, and subsequent actions, gave birth to the American Revolution and American Independence, making Philadelphia a centerpiece of early American history. It was the most populous city of the young United States, and served as the nation's first capital during much of the Revolutionary War and after. Following the ratification of the U.S. Constitution, it was the temporary national capital from 1790 to 1800 while Washington, DC was under construction.

Prior to the arrival of Europeans, the Philadelphia area was the location of the Lenape (Delaware) Indian village Shackamaxon. Europeans arrived in the Delaware Valley in the early 1600s, with the first settlements founded by the Dutch, British and Swedish.

The Swedes sought to expand their influence by creating an agricultural (tobacco) and fur-trading colony to bypass French and British merchants. The New Sweden Company was chartered and included Swedish, Dutch and German stockholders. The first Swedish expedition to North America embarked from the port of Gothenburg in late 1637. It was organized and overseen by Clas Fleming, a Swedish admiral from Finland. Part of this colony, called New Sweden or Nya Sverige eventually included land on the west side of the Delaware River from just below the Schuylkill River: in other words, today's Philadelphia, southeast Pennsylvania, Delaware, and Maryland.

In 1644, New Sweden supported the Susquehannocks in their victory in a war against the English province of Maryland. A series of events led the Dutch — led by governor Peter Stuyvesant — to move an army to the Delaware River in the late summer of 1655. Though New Netherland now nominally controlled the colony, the Swedish and Finnish settlers continued to enjoy a degree of local autonomy, having their own militia, religion, court, and lands. This status lasted officially until the English conquest of the New Netherland colony, in October 1663-1664, and continued unofficially until the area was included in William Penn's charter for Pennsylvania, in 1682.

In 1681, as part of a repayment of a debt, Charles II of England granted William Penn a charter for what would become the Pennsylvania colony. Part of Penn's plan for the colony was to create a city on the Delaware River to serve as a port and place for government. Despite already having been given the land by Charles II, Penn bought the land from the local Lenape to be on good terms with the Native Americans and ensure peace for his colony. According to legend Penn made a treaty of friendship with Lenape chief Tammany under an elm tree at Shackamaxon, in what is now the city's Kensington section. As a Quaker, Penn had experienced religious persecution and wanted his colony to be a place where anyone could worship freely despite their religion. Penn named the city Philadelphia, which is Greek for brotherly love (philos, "love" or "friendship", and adelphos, "brother").

William Penn's plan was that Philadelphia would be like an English rural town instead of a city. The city's roads were designed with a grid plan with the idea that houses and businesses would be spread far apart and surrounded by gardens and orchards. The city's inhabitants didn't follow Penn's plans and crowded by the Delaware River and subdivided and resold their lots. Before Penn left Philadelphia for the last time, he issued the Charter of 1701 establishing Philadelphia as a city. The city soon grew and established itself as an important trading center. Conditions in the city were poor at first, but by the 1750s living conditions had improved. A significant contributor to Philadelphia at the time was Benjamin Franklin. Franklin helped improve city services and founded new ones, such as the American Colonies' first hospital. Due to Philadelphia's central location in the colonies, during the American Revolution the city was used as the location for the First Continental Congress before the war, the Second Continental Congress, which signed the United States Declaration of Independence, during the war, and the Constitutional Convention after the war. A number of battles during the war were fought in Philadelphia and its environs as well. Unsuccessful lobbying after the war to make Philadelphia the United States capital helped make the city the temporary U.S. capital in the 1790s. In 1793, the largest yellow fever epidemic in U.S. history killed as many as 5,000 people in Philadelphia—roughly 10% of the population.

The state government left Philadelphia in 1799 and the federal government left soon after in 1800. However Philadelphia was still the largest city in the United States and a financial and cultural center. New York City soon surpassed Philadelphia in population, but construction of roads, canals, and railroads helped turn Philadelphia into the United States' first major industrial city. Throughout the 19th century Philadelphia had a large variety of industries and businesses, the largest being textiles. Major corporations in the 19th and early 20th centuries included the Baldwin Locomotive Works, William Cramp and Sons Ship and Engine Building Company, and the Pennsylvania Railroad. Industry, along with the U.S. Centennial, was celebrated in 1876 with the Centennial Exposition, the first official World's Fair in the United States. Immigrants, mostly German and Irish, settled in Philadelphia and the surrounding districts. The rise in population of the surrounding districts helped lead to the Act of Consolidation of 1854 which extended the city of Philadelphia to include all of Philadelphia County. In the later half of the century immigrants from Russia, Eastern Europe and Italy and African Americans from the southern U.S. settled in the city.

By the 20th century Philadelphia had become known as "corrupt and contented." Philadelphians were content with the city's lack of change or excitement, and single-party politics, centered on the city's entrenched Republican political machine, allowed corruption to flourish. The machine and corruption permeated in all parts of city government and reformers had little success. The first major success in reform came in 1917 when outrage over the murder of a police officer during that year's election led to the shrinking of the Philadelphia City Council from two houses to just one. In the 1920s the public flouting of Prohibition laws, mob violence, and police involvement in illegal activities led to the appointment of Brigadier General Smedley Butler of the U.S. Marine Corps as director of public safety, but political pressure prevented any long term success in fighting crime and corruption.

After a population peak of over two million residents in 1950 the city's population declined while the suburban neighboring counties grew. Revitalization and gentrification of neighborhoods began in the 1960s and continues into the 21st century, with much of the development in the Center City and University City areas of the city. After many of the old manufacturers and businesses had left Philadelphia or shut down, the city started attracting service businesses and began to more aggressively market itself as a tourist destination. Glass and granite skyscrapers were built in Center City. Historic areas such as Independence National Historical Park located in Society Hill were resuscitated during the reformist mayoral era of the 1950s through the 1980s and are now among the most desirable living areas of Center City. This has slowed the city's forty-year population decline after losing nearly a quarter of its population.

Architecture

Philadelphia's architectural history dates back to Colonial times and includes a wide range of styles. The earliest structures were constructed with logs, but brick structures were common by 1700. During the 18th century, the cityscape was dominated by Georgian architecture, including Independence Hall.

In the first decades of the 19th century, Federal architecture and Greek Revival architecture were dominated by Philadelphia architects such as Benjamin Latrobe, William Strickland, John Haviland, John Notman, Thomas U. Walter, and Samuel Sloan. Frank Furness is considered Philadelphia's greatest architect of the second half of the 19th century, but his contemporaries included John McArthur, Jr., Addison Hutton, Wilson Eyre, the Wilson Brothers, and Horace Trumbauer. In 1871, construction began on the Second Empire-style Philadelphia City Hall. Despite the construction of steel and concrete skyscrapers in the 1910s, '20s and '30s, the 548 ft (167 m) City Hall remained the tallest building in the city until 1987 when One Liberty Place was constructed.

Numerous glass and granite skyscrapers were built from the late 1980s onwards. In 2007, the Comcast Center surpassed One Liberty Place to become the city's tallest building.

For much of Philadelphia's history, the typical Philadelphia home has been the row house. The row house was introduced to the United States via Philadelphia in the early 1800s and, for a time, row houses built elsewhere in the United States were known as "Philadelphia rows". There is a variety of row houses throughout the city from Victorian-style homes in North Philadelphia to twin row houses in West Philadelphia. While newer homes are scattered throughout the city, much of Philadelphia's housing is from the early 20th century or older. The age of the city's homes has created numerous problems which has led to blight and vacant lots in many parts of the city, while other neighborhoods such as Society Hill, which has the largest concentration of 18th-century architecture in the United States, have been rehabilitated and gentrified.

Philadelphia contains many national historical sites that relate to the founding of the United States. Independence National Historical Park is the center of these historical landmarks. Independence Hall, where the Declaration of Independence was signed, and the Liberty Bell are the city's most famous attractions. Other historic sites include homes for Edgar Allan Poe, Betsy Ross, and Thaddeus Kosciuszko, early government buildings like the First and Second Banks of the United States, Fort Mifflin, and the Gloria Dei (Old Swedes') Church National Historic Site.

Philadelphia's major science museums include the Franklin Institute, which contains the Benjamin Franklin National Memorial, the Academy of Natural Sciences, and the University of Pennsylvania Museum of Archaeology and Anthropology. History museums include the National Constitution Center, the Atwater Kent Museum of Philadelphia History, the National Museum of American Jewish History, the African American Museum in Philadelphia, the Historical Society of Pennsylvania, the Grand Lodge of Free and Accepted Masons in the state of Pennsylvania and The Masonic Library and Museum of Pennsylvania and Eastern State Penitentiary. Philadelphia is home to the United States' first zoo and hospital.

Shopping areas

• Franklin Mills - A large outlet and discount shopping mall in the Far Northeast section.
• The Gallery at Market East - Shopping mall in Center City.
• Italian Market - Open produce and meat market with many specialty shops.
• Jewelers' Row - Two densely packed blocks of jewelers and related shops.
• Reading Terminal Market - Large enclosed produce, meat and prepared food market featuring some Pennsylvania Dutch merchants and others.
• The Shops at Liberty Place - Upscale shopping mall inside the skyscraper complex known as Liberty Place.
• South Street - Many trendy and counterculture shops between Front and 10th Streets.
• Walnut Street - Many expensive shops between Broad and 20th Streets and the surrounding area.
• Wanamaker's (now Macy's) - Defined the department store and remains a landmark. Features the Wanamaker Organ.