Subterranean Sites

The "Great Sewer" of ancient Rome is one of the oldest sewer systems in the world, and is still in use.

This Cold War–era underground city includes offices for Mao Zedong and Lin Biao.

This network of tunnels housed an entire village for years, and even had a hall for screening movies.

The giant Siberian crater known locally as the "doorway to the underworld" is expanding every year.

A subterranean shelter remains intact under a busy Paris railway station.

A 19th-century subterranean reservoir repurposed as a contemporary art cave.

Members of Congress have traveled between the buildings on Capitol Hill for a century hidden from tourists, press, and storm clouds.

A mistaken marker makes an erroneous claim along the historic Old Divide Road.

Underground vaults of a former brewery beneath Brooklyn's Crown Heights are now used to ripen cheese.

The world's longest and deepest train tunnel.

Beautiful mosaics cover the first stations opened on New York City's newest subway line.

An elegant chandelier hangs over this ancient sewer chamber, now open for concerts and public tours.

Long-abandoned trolley tunnels just a mile away from the White House are turning into an art space.

Hamburgers are intensely proud of their tunnel beneath the river.

A century-old network of freight tunnels underneath the city's historic business district.

One of the most breathtaking railways in Europe also takes one of the steepest climbs, from fjord to mountain plateau.