Eastern State Penitentiary

Philadelphia's Eastern State Penitentiary first opened in 1829 with an unusual penal premise: reform criminals by keeping them imprisoned in complete isolation -- better-known today as solitary confinement. A number of high-profile criminals were imprisoned here over its 142-year history, including Al Capone, whose well-decorated cell can be seen during a tour of the facility. Eastern State has long been said to be haunted, and a number of television shows, including Ghost Adventures, have explored the paranormal while filming here. Each Halloween, the structure is converted into the famous "Terror Behind the Walls" haunted house.

Franklin Court

Visit the site where Benjamin Franklin's house once stood in what is now called Franklin Court. Franklin was serving as emissary to England and France during most of the home's construction, and his wife, Deborah was responsible for overseeing much of its construction. Franklin ultimately died here in 1790, and the house was eventually demolished in the early 1800s. Today, the site lies tucked between the hubs of Market St. and Chestnut St. and visitors must pass through a brick archway to reach the site.

Philadelphia Zoo

Zoo lovers flock (yes, pun intended) to America's oldest zoo, opened in 1874, to marvel at the 42 acres of habitats filled with more than 1,300 animals. Located in West Fairmount Park in a Victorian garden-like setting, the zoo's highlights include Big Cat Falls, home to tigers, lions, leopards and jaguars, as well as the McNeil Avian Center, a rainforest habitat where visitors will discover more than 100 bird species, including many rare and endangered ones, from around the globe.

Liberty Bell

The Liberty Bell -- and its memorable crack -- stands as America's most iconic symbol of independence and liberty. Commissioned in 1751 for the Pennsylvania State House and cast in England, the 2,000-lb. bell cracked shortly after it was brought to America. It was recast using metal from the original bell, and yet, even the new bell wasn't without flaw. Upon being rang in 1846 to commemorate George Washington's birthday, the bell cracked again, and has not been rung since. Today it is housed in a 13,000-square-foot glass gazebo, a structure which also features numerous interactive history displays.

Franklin Square

Philadelphia is a city of bucolic squares, and Franklin Square is one of the five original ones laid out by William Penn in his city plan. A stunning marble fountain dating back to 1838 serves as the 7.5-acre square's centerpiece, but visitors, particularly the wee ones, tend to be more enamored with the adjacent Philadelphia Park Liberty Carousel, a nearby 18-hole miniature golf course and the tasty SquareBurger hamburger stand.

Betsy Ross House

Though historians may debate the veracity of whether Betsy Ross truly did sew our nation's first flag of 13 stars and 13 stripes, visitors can learn about the life and times of the famed seamstress on a tour of the Betsy Ross house. This tiny, well-restored property on Arch Street is one of the city's most popular historic attractions. Ross is believed to have rented the home, and having been newly widowed, worked as a seamstress and upholsterer, often sewing flags for American ships.

Independence Hall

As the site of the signing of both the Declaration of Independence in 1776 and the U.S. Constitution in 1787, Independence Hall ranks as one of America's most important historic landmarks. Guided tours of the Hall convene in the courtroom where the 56 brave men defied the King of England by signing the Declaration and then continued to the Assembly Room where 11 years later delegates from 12 colonies convened to set forth the nation's principles of freedom and democracy in the Constitution.

Elfreth's Alley

Dating back to 1702, Elfreth's Alley has earned its title of "our nation's oldest residential street." Indeed, the narrow, storied alleyway is America's oldest continuously inhabited street, and this meticulously maintained cobblestone and brick throughway is a charmer. Twice a year, in June and during the Christmas holidays, residents open their houses up for visitors to tour. Two of the homes have been converted into the Elfreth's Alley Museum, open year-round. 

United States Mint

In 1792, when Philadelphia served as the nation's capital, the Coinage Act proclaimed the creation of the United States Mint. The opening of the Mint helped establish the fledgling nation's identity, and now, more than 220 years later, at least half of America's circulating coins are still produced here. Free, self-guided tours allow visitors to learn the steps of the minting process, watch the current minting process from high above the production floor on a catwalk, and see the nation's first coining press from 1792.