Named for a prominent scout and explorer, this Wyoming state park encompasses a replica of an 1840s trading post, a 19th-century Army outpost, and early 20th-century automobile lodgings.

The remains of a 13th-century Romanesque church lie abandoned on a hillside.

This replica of a 16th-century French settlement memorializes one of the earliest attempts at a European settlement in North America.

A military fort has guarded the surrounding area from this key position since the 13th century.

The haunting remains of a World War I fort perched atop a mountain.

A replica of a fort built from a frontier town's mass hysteria in the face of false reports of impending Native American violence.

Believed to be the capital of the the ancient kingdom of Dál Riata.

This historic fort spans more the 300 years.

A Spanish Colonial fort now houses an archeology museum.

The ruins of a military fortification sit atop this mountain.

Beneath the southern end of the Golden Gate Bridge is the “Gibraltar of the West Coast,” a fort built to protect the San Francisco Bay from naval attack.

This coastal port saw one of the most significant battles of the Civil War.

A nearly impregnable 16th-century fort is one of Goa's oldest.

Historic seaside park featuring explorable, abandoned military structures.

This 17th-century Portuguese fort now houses a nautical museum.

This 17th-century fort, built by the Dutch to control a piece of the international spice trade, is now a city park.