Founded in 1682 by William Penn, Philadelphia quickly became the most important city in the New World. The Declaration of Independence was written here. So was the Constitution. In the 19th century, it became a philosophical hub, with societies such as the Academy of Natural Sciences and Franklin institute founded.
Immigrants, mostly from Ireland and Germany, began arriving in Philly and quickly began fighting for worker rights. The 1835 Philadelphia general strike was the first of its kind in America and resulted in total victory for the workers.
Tens of thousands of black Americans came up to Philly from the South during the Great Migration, founding hundreds of businesses, newspapers such as the Philadelphia Tribune, and Douglas Hospital. Civil Rights leaders such as Octavius Catto fought for and won the right to vote and the desegregation of streetcars.
Italian immigrants began arriving en masse in Philadelphia in the 1880s, with most of them coming from the Abruzzi region, and many found a home in South Philly. They brought with them much of the cuisine and culture Philly is famous for.
The 20th century saw industrialization reach its peak; over 35% of the city's workers worked in the textile business by 1904. The ensuing deindustrialization and globalization were not kind to the city. Suburbs expanded rapidly, and subsequently the city's tax base shrank. By the 1980s, the post-Industrial city was approaching bankruptcy.
But with an emphasis on the service industry and tourism, and increased immigration from countries like Mexico, China, and Vietnam, this great American city began to rise again. After hemorrhaging population starting after World War II, the city's population finally began to grow again in the 2000s. It has grown about 5% in the past 20 years, and its combination of grit, charm, never-say-die attitude, and brotherly love have it poised to become one of America's most important cities of the 21st century.