Wrapped in layers of fascinating history, Philadelphia was the nexus of the nation's original 13 colonies, acting as an 18th century hotbed of political activism that gave rise to the American Revolution. Under the canopy of downtown Center City's spectacular skyscrapers, the ivy-covered buildings of Independence National Historical Park and the many structures dating back to the 1700s lend the city an aged feel unlike any other U.S. metropolis. Philadelphia's citizens are hardy, loyal to their city and extremely proud of their endlessly rich cultural climate. The city's unique culinary contribution is the Philly cheesesteak, sliced steak and cheese served on a roll, with both Pat's King of Steaks and Geno's Steaks in southern Philadelphia laying claim to the recipe's invention.