Playable, historic pinball machines fill this Alameda museum.

Australian Lake set aglow by Noctiluca Scintillans.

A modernist landscape of water and sci-fi concrete.

The only swimming pool listed on the National Register of Historic Places is emptied and refilled each day with naturally filtered water.

Ruined 11th century abbey built by King David I in Edinburgh, Scotland.

A Swedenborgian glass church surrounded by redwoods sits perched atop a massive landslide area.

Stalactites and stalagmites in a beautifully lit cave.

The largest hot spring in the United States is, as the name suggests, a stunning show of natural color.

A stunning, two-tiered waterfall made famous by poets, artists and the legend of a ghost dog.

A series of modernist treehouse hotel rooms grace the outskirts of an Arctic forest.

What was once the largest NFL stadium.

A Hawaiian stairway to heaven—that you can't climb.

A beautiful geyser under environmental threat.

Every autumn, this hillside is ablaze with red summer cypress.

Centuries-old bridges grown from tangled roots.

Pompeii's less famous neighbor is still revealing her secrets.

Kings Cross Station pays tribute to its role in Britain's best-selling book series.

An ethereal glowing blue ocean cave in Croatia.

Stroll through a wonderland of stupendous moss-covered trees.

A gargantuan crystal kingdom.

Keshwa chaca, among the last handwoven Incan bridges, crosses Apurimac Canyon in Peru.

An Aztec snake god has taken the material form of an apartment complex.

Ruins of a German Castle on top of a towering stone pillar.

In this historic region, homes and churches are carved into ancient volcanic rock formations.