Philadelphia International

In the most densely populated state in the country sits a wilderness most Americans don't know exists: the Pine Barrens, over a million acres of pine-oak forest, cedar swamps, and tea-colored rivers covering roughly a fifth of New Jersey. The sandy, acidic soil grows pines instead of farms — early colonists called it "barren" — and beneath it lies the Kirkwood-Cohansey aquifer, 17 trillion gallons of some of the purest water in the country. It's a place of cranberry bogs and blueberry fields, ghost towns from the old bog-iron industry, and the legend of the Jersey Devil. Tannins from the cedar stain the streams the color of dark tea. From the air it's a startling carpet of unbroken green in the middle of the Boston-Washington megalopolis.

Founded in 1746, Princeton is one of the oldest universities in America and among the most beautiful — a campus of collegiate Gothic towers, ivy, and courtyards in a leafy New Jersey town. Nassau Hall, built in 1756, was the largest stone building in the colonies, briefly served as the capitol of the United States in 1783 (the Continental Congress met here), and still bears scars from a cannonball fired during the 1777 Battle of Princeton. The town and university have hosted an extraordinary concentration of minds: Albert Einstein spent his last decades here at the Institute for Advanced Study, walking to his office on Mercer Street, and the campus and town have appeared in everything from "A Beautiful Mind" to F. Scott Fitzgerald's novels.

The 1921 Hangar No. 1 at Lakehurst — National Historic Landmark, 966 feet long, large enough to hold the Hindenburg with room to spare. Where four U.S. Navy rigid airships (Shenandoah, Akron, Macon, plus borrowed Los Angeles) were based 1921-1939. The actual 1937 disaster site is marked by a chain-link outline of where Hindenburg fell, with a memorial plaque listing the 36 dead. The Navy Lakehurst Historical Society runs guided tours by appointment (security clearance required — it's an active military base). Among the largest interior volumes of any wood-frame structure ever built, the hangar still has the original "ship" mooring rails on its floor. The most famous 32 seconds in aviation history happened 200 yards from the front door.

The first boardwalk in the world opened in Atlantic City in 1870 — built to keep beach sand out of the hotels and railcars — and the city became the great American seaside playground, the "World's Playground," at its height in the early 20th century. Its street names became so iconic that they were borrowed for the board game Monopoly (Boardwalk, Park Place, the rest). The skyline of casino towers rose in the late 1970s when New Jersey legalized gambling, the second US city after Las Vegas. The wide boardwalk, the Steel Pier amusement rides jutting over the surf, the casinos, and the long barrier-island beach are the draw — a faded-and-revived monument to American leisure on the Jersey Shore.