For more than two centuries, the canopy of this venerable tree has been a haven for songbirds and lovers.

One Portuguese poet described this cape, the westernmost point in mainland Europe, as "where the land ends and the sea begins."

This eccentrically decorated palace is replete with grottoes, fountains, tunnels, and caves.

An ancient and majestic fortress that played an integral role in Portugal's road to independence.

This unreal Portuguese palace looks as though it's made from a pile of different castles.

A king's pet, a pope's gift, an artist's inspiration, and a tragic shipwreck.

Elaborately carved to showcase the glorious wealth that the age of exploration brought to the Portuguese empire.

Eat the ultimate iteration of Portugal's most beloved pastry.

Step back in time at this 19th-century kiosk.

Portugal's National Pantheon has a history of curses, collapses and financial problems.

This Industrial Age architectural and engineering gem helps visitors and residents alike traverse Lisbon, “The City of Seven Hills.”

Sip cherry liqueur at a bar dating back to 1840.

Maryland's first (and last standing) toll house on America's first federal road established the state as the "Gateway to the West."

Once home to seven different roller coasters, Glen Echo has undergone many transformations since its founding in 1891.

The Byzantine, pre-Columbian, and medieval art at this stately mansion are some of the most under-appreciated collections in D.C.

This small hilltop church weaves the urban history of Washington, D.C. with the national history of the United States.

A historic estate packed with George Washington's heirlooms, and its own nuclear bunker.

A painfully obvious spy house sits right across the street from the Russian Embassy.

A brass and marble scale model of the solar system embedded in the concrete.

A bas relief commemorates the "Nuns of the Battlefield" who cared for soldiers on both sides of the conflict.

This grand gothic brewery has been pumping out suds for over a hundred years.

A small triangle of DC grass is the final resting place of one of Sonny and Cher's songs.

With over 100 jam-packed rooms to explore plus elaborate tea services and events, the Mansion on O Street is a hidden treasure.

The graveyard holding the remains of George Washington's slaves was forgotten for nearly 200 years.