The remains of what was, not so long ago, the world's largest city.

An ancient iron pillar in Delhi that seems to be rustproof.

A blooming house of worship for the masses.

Ha Long Bay's "Cave of Surprises" houses a popular phallic rock formation.

A white Buddhist temple with a golden restroom.

Ho Chi Minh's perfectly preserved body has been on display here since 1975.

One of Antoni Gaudí's most classic buildings is well-known for its "dragon-back" design.

Construction of Barcelona's iconic (but controversial) church is expected to be completed in 2026—a century after the death of its architect.

Cold war icon and onetime "hole" in the iron curtain.