Clap your hands at the base of the pyramid, and the song of a sacred Mayan bird will echo through the air.

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

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

Its sunny hues are believed to have inspired the town's color palette.

A hidden treasure of an abandoned city lies deep in the jungles of Campeche, Mexico.

At least seven hues of blue and turquoise make this freshwater lagoon unique.

The struggle of a small Dutch island against the sea.

The deepest underground city in Turkey was designed to protect 20,000 people behind massive stone doors.

This giant statue is the product of a mixture of corruption, Stalinist architecture, and North Korean manpower.

This tiny, tranquil Senegalese island serves as a powerful symbol of the Atlantic slave trade.

A 19th-century architectural masterpiece with ties to Gustave Eiffel.

A tree seems to grow from the ocean floor on this strange strip of sand slowly being overtaken by the sea.

Serbia's master of striking memorials erected a forgotten, hidden gem in the hills outside a tiny village.

The interior of this Serbian royal family's mausoleum is covered with exquisite mosaics.

This memorial park stands on the site of one of the largest mass executions of the Second World War.

This old KLM airplane cut into three parts was transformed into an eclectic airport gift shop.

An enormous and lavish Gothic church in Czechia.

A church of bones, decorated with 40,000 human skeletons.

Straight out of a nightmare, barcode-faced babies climb up and down Prague's television tower.

Steadily reminding Czechia of its past.

Monument to a suicide protesting the Soviet invasion.

This walkway is so narrow it needs its own light to stop pedestrian traffic jams.

Looming communist pillar with a Czech twist.

Despite attempts by local police to discourage it, Beatles-inspired graffiti has been a means for artists to air grievances for decades.