Short answers, pulled from the story.
Philadelphia was founded in 1682 by William Penn, an English Quaker who arrived in the Delaware Valley to establish a colony based on religious tolerance and peace. Penn negotiated a treaty with Lenape chief Tammany under an elm tree to ensure the local Lenape people were treated with respect rather than conquest.
Philadelphia hosted the First Continental Congress in 1774 and the Second Continental Congress from 1775 to 1781, where the Declaration of Independence was adopted on the 4th of July 1776. The city served as the nation's capital from 1790 to 1800 and hosted the Constitutional Convention in 1787, which ratified the Constitution on the 17th of September 1787.
Philadelphia became the first major industrial city in the United States during the 19th century, with the textile industry leading the way and major corporations like the Baldwin Locomotive Works and the Pennsylvania Railroad driving economic growth. The city witnessed the first general strike in North America in 1835, when workers won the ten-hour workday.
Philadelphia established the nation's first library in 1731, the first hospital in 1751, the first medical school in 1765, and the first zoo in 1874. The city also hosted the first official World's fair in the U.S. at the Centennial Exposition of 1876 and became home to the first modern International Style skyscraper in the United States, the PSFS Building, in 1932.
Philadelphia's population peaked at more than two million residents in 1950, but suburbanization and the restructuring of industry led to a long decline. The city lost about 25 percent of its residents between 1950 and 2000 before population growth resumed in 2007.
Philadelphia's modern economy is driven by financial services, health care, biotechnology, information technology, and trade and transportation, with the city being home to five Fortune 500 companies. The city has the second-largest Irish and Italian populations in the United States after New York City and hosts the second-largest Puerto Rican population on the U.S. mainland after New York City.