Title: Philadelphia
Content:  Philadelphia (colloquially known simply as Philly) is a city in the Commonwealth of Pennsylvania in the United States. It is the sixth-most-populous city in the United States and the most populous city in the state of Pennsylvania, with a 2020 population of 1,603,797. It is also the second-most populous city in the Northeastern United States, behind New York City. Since 1854, the city has had the same geographic boundaries as Philadelphia County, the most-populous county in Pennsylvania and the urban core of the eighth-largest U.S. metropolitan statistical area, with over 6 million residents. Philadelphia is also the economic and cultural center of the greater Delaware Valley along the lower 
Title: Nicknames of Philadelphia
Content:  Philadelphia has long been nicknamed "The City of Brotherly Love" from the literal meaning of the city's name in Greek (Φιλαδέλφεια, "brotherly love"), derived from the Ancient Greek terms φίλος phílos (beloved, dear, or loving) and ἀδελφός adelphós (brother, brotherly). The city was first named by its founder, William Penn. "Philadelphia" is also frequently shortened to simply Philly. The Philadelphia Phillies, the city's baseball team, officially formed in 1883.
Title: Outline of Philadelphia
Content: Pronunciation: ; Common English name(s): Philadelphia ; Official English name(s): City of Philadelphia ; Nicknames of Philadelphia ; Philly ; The City of Brotherly Love ; Adjectival(s): Philadelphian ; Demonym(s): Philadelphians ; Rankings ; largest city in Pennsylvania ; second largest city on the East Coast ; fifth-most populous city in the U.S. 
Title: Nicknames of Philadelphia
Content: "The Athens of America" - So called as early as 1733 by the directors of the Library Company of Philadelphia. Gilbert Stuart referred to the city using this phrase, referring to Philadelphia's reputation for science, industry, art, and intellectual life. ; "The Birthplace of America" - derived from Philadelphia's role in the American Revolution and location of the signing of the Declaration of Independence and Constitution ; "The Cradle of Liberty" - derives from Philadelphia's role in the American Revolution. Also a nickname of Boston. ; "The Quaker City" - was given in reference to the religion of the city's early settlers. ; "The Workshop of the World" - Philadelphia's Industrial Revolution history gave it this nickname; in the 
Title: Nicknames of Philadelphia
Content:  city of residences" in a book published in 1893, referencing the city's high levels of home ownership. The nicknamed refers to the city's many distinct neighborhoods and sense of neighborhood pride. ; "The City That Bombed Itself" - In 1985, Philadelphia police bombed a rowhouse occupied by MOVE, a radical black-power group. The bombing killed 11 people, destroyed 61 homes, left 250 people homeless, and earned the city this title. ; "Filthadelphia" or "Filthydelphia" - a reference to the omnipresent trash on the streets ; "The Sixth Borough" - a reference due to Philadelphia's close proximity to New York City and the movement of New Yorkers to Philadelphia for less expensive rents, real estate, and cost of living. 
Title: Outline of Philadelphia
Content:  The following outline is provided as an overview of and topical guide to Philadelphia: Philadelphia – largest city in the Commonwealth of Pennsylvania, the second largest city on the East Coast of the United States, and the fifth-most-populous city in the United States. It is located in the Northeastern United States along the Delaware and Schuylkill rivers, and it is the only consolidated city-county in Pennsylvania. As of the 2010 Census, the city had a population of 1,526,006, growing to 1,547,607 in 2012 by Census estimates. Philadelphia is the economic and cultural center of the Delaware Valley, home to over 6 million people and the country's sixth-largest metropolitan area. 
Title: Gentrification in Philadelphia
Content:  Philadelphia serves as an example of urban growth, decline, and regrowth along with other industrial cities of the northeast United States: Worcester, Massachusetts, Providence, Rhode Island, Newark and nearby Trenton, New Jersey. Philadelphia has a longer history and arguably richer provenance than its competitor cities. It has a deepwater port and was the first capital of the United States.  Development in Philadelphia began along the Delaware, at Penn's Landing, at a spot that enjoys a close approach of the Schuylkill River two miles to the west. Near the Delaware River are the oldest neighborhoods and Independence Hall. Development continued westward 
Title: Philadelphia
Content:  granted Penn a charter for what would become the Pennsylvania colony. Despite the royal charter, Penn bought the land from the local Lenape to be on good terms with the Native Americans and ensure peace for his colony. Penn made a treaty of friendship with Lenape chief Tammany under an elm tree at Shackamaxon, in what is now the city's Fishtown neighborhood. Penn named the city Philadelphia, which is Greek for "brotherly love," derived from the Ancient Greek terms φίλος phílos (beloved, dear) and ἀδελφός adelphós (brother, brotherly). There were a number of cities named Philadelphia in the Eastern Mediterranean during 
Title: Philadelphia
Content:  library, and one of the American colonies' first hospitals. A number of philosophical societies were formed, which were centers of the city's intellectual life: the Philadelphia Society for Promoting Agriculture (1785), the Pennsylvania Society for the Encouragement of Manufactures and the Useful Arts (1787), the Academy of Natural Sciences (1812), and the Franklin Institute (1824). These societies developed and financed new industries, attracting skilled and knowledgeable immigrants from Europe. Philadelphia's importance and central location in the colonies made it a natural center for America's revolutionaries. By the 1750s, Philadelphia had surpassed Boston to become the largest city and busiest port in 
Title: Nicknames of Philadelphia
Content:  War II 20th century, Philadelphia "led the nation in production of such diverse products as locomotives, streetcars, saws, steel ships, textiles, rugs, hosiery, hats, leather, and cigars. It held second place in the production of sugar, fertilizer, foundry castings, petroleum, products, chemicals, and drugs." ; "The City that Loves you Back" - this slogan was introduced by the Greater Philadelphia Tourism Marketing Corporation (GPTMC) in a 1997 advertising campaign. The motto was both "a reply and a challenge to the 'I Love New York' slogan" and countered the "antisocial reputation" that Philadelphia had developed. ; "The City of Neighborhoods" - unclear how this name emerged; Philadelphia was called "The City of Homes" by the 1870s, and was called 

Question: philadelphia is known as the city of what?
Answer: City of Brotherly Love.
Brotherly Love.