The walls of America's oldest masonry fort famously "swallowed" cannonballs.

An 18th-century Spanish watchtower made entirely of seashell and concrete.

Standing in a state of "arrested decay," this ghost town allows for a detailed peek into Gold Rush life in an unusually harsh climate.

Strange red rock formations that have been attributed to a higher power for hundreds of years.

A former waterfront market is now in the center of town due to some interesting Boston engineering.

Mrs. Mallard and her brood are a beloved fixture in Boston Public Garden.

The highest point in the state of New Hampshire, and while unlikely "the worst weather in the world," it sure seems that way to hikers.

Even Henry David Thoreau found this glacial pothole irresistible.

Looming communist pillar with a Czech twist.

In all of the 29 years it was in operation, no prisoners ever escaped successfully... or so they claim.

Gaudí's famously flamboyant architectural style is on full display in this sprawling park and garden.

Construction of Barcelona’s iconic (but controversial) church was finally completed in 2026—a century after the death of its architect.

Once the home of a hermetic monk, this cave now houses a small church.

This eccentrically decorated palace is replete with grottoes, fountains, tunnels, and caves.

On any given day this sprawling market houses literally tons of government-regulated gold, gems, and precious metals.

This sweet-toothed bear searching for snacks has been a symbol of Madrid for decades.

A display of torture devices used in the Spanish Inquisition and other scourges of medieval Europe.