Historic fortifications form the boundary of Vatican City, but it’s not entirely surrounded by walls.

The world's seventh-largest coral reef contains an incredible amount of biodiversity.

This spectacular mosque houses the second-largest chandelier in the world.

A staggering number of rock carvings in an abandoned quarry.

Where artisans use centuries-old techniques to build traditional Arabian ships.

A sinkhole and now a swimming hole, too, full of dazzling turquoise water.

An imposing Omani fortress surrounded by date palm trees.

Nature's water park in the Wadi Bani Awf valley is full of pools flanked with cliffs and natural water slides.

Groups of prehistoric tombs that dot the mountains of northern Oman.

This bazaar is one of the oldest in the Arabian world.

Climb down into the largest sinkhole in Qatar.

St. Mary's features one of the most spectacularly decorated cathedral interiors in all of Europe.

One of the holiest Shi'i shrines in Iran honors the life and death of a learned noblewoman who became a saint.

A nearly abandoned Jewish settlement perched atop a hill in the heart of Yemen.

The fierce beast perches atop a pedestal marking where the historic City of London gates once stood.

These underground shelters dug by the Japanese during World War II later helped East Timor achieve its independence.

Hundreds of caves filled with thousands of centuries-old statues and murals.

The world's largest frame offers spectacular views of the city's past and present.

Mysterious Incan ruins on a tiny island in Lake Titicaca.

A paradisical gorge with rapids, waterfalls, and wildlife whose raw beauty is the stuff of CGI movies.

Fantastic views and thousands of love locks.

Climb atop one of the world's longest and heaviest trains for an unbelievable journey across the Sahara Desert.

An extravagant monument to an extravagantly unpopular Emperor.

More than 100 Hindu temples are slowly being swallowed by the forest.