Air Force Academy Chapel made of 100 identical tetrahedrons works to inspire those of all religions.

This cave holds a surprisingly colorful variety of geological oddities.

A bizarre house filled with an astounding array of collections.

Relics of the 1894 Midwinter Exposition continue to delight visitors today.

Concrete strongholds stand guard over the Golden Gate.

A controversial memorial at the place where Captain Cook met his violent end.

Earth's tallest volcano is sacred to Native Hawaiians, and home to a dozen world-class observatories.

A tribute to the twin ideals of religion and patriotism, built by a Catholic priest from rocks, glass, and innumerable found items.