With a floor made of thick glass, this observation deck offers a full view of Sunwapta Valley's mountains and rivers.

A stone arch leads to a cavernous 1930s spring house tucked away in the Pennsylvania woods.

A grandiose title could not save this mercantile community from obscurity.

Enormous lake at the bottom of a unique cave system.

Exact replica of the ancient monument, but much, much lighter.

A cement mixer-turned-kaleidoscope in downtown Norfolk offers different views of the city.

Contrary to what one might expect, ice forms inside this small cavern during the summer and melts during the winter.

This geothermal hot spring hides beneath a slowly growing mineral dome.

An echo chamber with a waterfall wrapped around its base at the Embassy of Canada in Washington, D.C.

This abandoned amusement park was built on a site with a dark history.

The world's largest kaleidoscope, designed by a 1960s psychedelic artist.

This massive stained-glass masterpiece is thought to be the largest Tiffany dome in existence.

Georges Seurat’s pointillist masterpiece has been recreated in Ohio in topiary form.