The longest living non-clonal organisms on Earth.

A whimsical, punny collection of "fence art" outside the tiny mountain town of Baker, Nevada.

Ancient pueblos built into the base of a natural canyon wall.

This Arizona observatory is famous for investigations into Martian life, and as the place humans first spotted Pluto.

The installation’s official name, “You Who Are Getting Obliterated in the Dancing Swarm of Fireflies,” says it all.

The world's largest military aircraft cemetery.

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

Once a lonely sentinel on the edge of the Great Plains, this rebuilt trading fort offers a glimpse of life on the Santa Fe Trail.

Once at the center of U.S. finance, the historic Trading Room was meticulously recreated piece by piece and rebuilt in the Art Institute.

A unique botanical garden housed in three giant geodesic domes.

A multi-storied adobe complex has been inhabited for more than a thousand years.

Conflicting markers on its floor tell a tale of two city centers in San Antonio.

Legend has it the commander of the defenders drew a fateful line in the dirt with his sword just before the final battle.

In Twickenham sits a small whitewashed castle that inspired Mary Shelley's 'Frankenstein.'

Regency-era excess on the English Coast.

The rotting skeleton of a shoreside fun fair that was destroyed by fire and storms still haunts the Brighton ocean view.

The granddaddy of English geoglyphs dates back to the late Bronze Age.

A lush indoor jungle fills this bustling Madrid transportation hub.

Madrid's romantically ornate crystal palace has been offering shelter to plants and art for over a century.

Construction of Barcelona's iconic (but controversial) church is expected to be completed in 2026—a century after the death of its architect.

Holy Grotto of Montserrat Monastery holds one of Europe's mysterious black Madonnas.

Modest by day, illuminated majestically at sunset.

A Mexican Romeo-and-Juliet-esque legend has given this super-narrow alleyway a reputation for romance.

Mexico's astounding mummy museum with "the world's smallest mummy."