This picturesque Umbrian city has a subterranean side that has long remained hidden.

This massive mural by famed pop-artist Keith Haring was hidden for almost 30 years until its 2018 rediscovery.

A botanically themed auditorium blooms within the world’s last operating double-decker theater.

One of Canada's most incredible rare book collections holds hundreds of thousands of gorgeous tomes that the general public can touch.

Sleep in a glass pod dangling off a cliff.

The mortal remains of an estimated 70,000 people lie in the basement of a monastery in Lima, Peru.

A Christian monastery stands on what was once a holy Incan temple.

Built on the remains of one the Incas’ most important gathering spots, this square keeps the spirit of a fallen empire alive.

Situated on a sacred Inca site, this 16th-century cathedral took nearly 100 years to build.

The large collection of pre-Columbian pottery might make you blush.

A painting in the historic Cathedral Basilica depicts Jesus and his disciples dining on a traditional Peruvian menu.

The Uros people live on floating reed islands in lake Titicaca.

The stones of this Incan wall complex fit together so well you couldn't fit a piece of paper between some of them.

Preserved Inca city and site of the last Inca stronghold against the Spanish conquistadors.

The intricate stonework of Machu Picchu serves as a testament to Incan engineers.

A place for ship-lovers to watch the passage of freighters traversing the Great Lakes while learning about their history.

A charming remnant of 19th-century fishing towns sits on Michigan’s Leelanau Peninsula.

This national park on the shore of Lake Michigan features remarkable dunes that lie at the heart of a Chippewa legend.

A magical sinkhole on the Yucatán Peninsula is adorned with mini waterfalls and hanging vines.

No telescopes, no power, no gift shop: The Observatory of Chichen Itza, one of the world's oldest observatories, takes astronomy back to basics.

Every equinox this Maya pyramid puts on a spooky ancient light show.

Legacy of the earthquake that nearly wiped Lisbon off the face of the Earth.

An unassuming music museum recounts the rags to riches story of a dramatic Portuguese genre.

The iconic boulevard is the perfect place to catch sight of a bicycling skeleton, a levitating Satan, or a chef with his head stuck in a pizza.