Sister Library of Alexandria in Alexandria, Egypt

Underneath the Serapeum ruins lies a dark passage with nooks for books, the lesser-known “sister” to the famous ancient library.#ancientegypt #ancient #subterraneansites #ruins #libraries #section-Atlas
Sister Library of Alexandria

Lascaris War Rooms in Valletta, Malta

Both the World War II Allied Forces and NATO have used this modern bunker underneath Malta’s capital.#militaryhistory #worldwarii #subterraneansites #bunkers #underground #section-Atlas
Lascaris War Rooms

Shakpak-Ata in Ashchimuryn, Kazakhstan

A remote, centuries-old underground mosque with a lunar aesthetic.#history&culture #archaeology #subterraneansites #zoroastrianism #religion #caves #mosques #section-Atlas
Shakpak-Ata

Tham Nang Ene Cave in Xiangliab, Laos

Mythological depictions of Laos’ national animal make this cave sacred.#sacredspaces #subterraneansites #history&culture #elephants #geology #caves #section-Atlas
Tham Nang Ene Cave

King Solomons Cave in Liena, Australia

A limestone cave filled with impressive formations in Mole Creek Karst National Park.#nationalparks #naturalwonders #geology #subterraneansites #underground #caves #section-Atlas
King Solomons Cave

Sand Cave in Ewing, Virginia

Erosion has transformed this sandstone boulder into a massive dune-filled cavern.#geology #subterraneansites #underground #caves #section-Atlas
Sand Cave

Gruta de las Maravillas (Cave of Wonders) in Aracena, Spain

An underground spring in a labyrinthine cave system, decorated with stalagmites and stalactites.#minerals #geologicaloddities #geology #underground #subterraneansites #caves #section-Atlas
Gruta de las Maravillas (Cave of Wonders)

Belly of the Dragon in Orderville, Utah

Nature has shaped this drainage tunnel into the digestive tract of a mighty beast.#highways #subterraneansites #geology #tunnels #section-Atlas
Belly of the Dragon

REGAN Vest in Skørping, Denmark

Deep in the forest of northern Denmark, this secret underground bunker was built at the height of the Cold War.#subterraneansites #coldwar #bunkers #section-Atlas
REGAN Vest

Cueva de Valporquero in Vegacervera, Spain

The spectacular geological formations make it one of the most impressive caves in Europe.#geologicaloddities #geology #subterraneansites #underground #caves #section-Atlas
Cueva de Valporquero

Taya Caves in Yokohama, Japan

A network of ancient tunnels and vaulted chambers with mystical Buddhist reliefs, built for ascetic training.#tunnels #monks #buddhism #subterraneansites #underground #caves #section-Atlas
Taya Caves

Cueva del Indio in Viñales, Cuba

Besides being home to cave paintings and pre-Columbian Cuban archaeological remains, you get to take a boat through this stalactite and stalagmite covered caved.#rivers #underground #subterraneansites #caves #section-Atlas
Cueva del Indio

Le Gouffre de Padirac (Padirac Cave) in Padirac, France

This impressive chasm is one of the longest natural underground cavities in the world.#legends #rivers #subterraneansites #underwater #caves #section-Atlas
Le Gouffre de Padirac (Padirac Cave)

Asakusa Underground Street in Tokyo, Japan

Stuck in a bygone era, the oldest subterranean shopping street in Japan hides beneath the popular Asakusa district of Tokyo.#tunnels #shopping #subterraneansites #underground #section-Atlas
Asakusa Underground Street

Downtown Houston Tunnel System in Houston, Texas

The largest underground pedestrian tunnel system in the U.S. mostly caters to the people working in the offices above, but provides a great, air-conditioned way to traverse the city.#architecturaloddities #subterraneansites #underground #tunnels #section-Atlas
Downtown Houston Tunnel System