Two-thousand-year-old earthworks that demonstrate the Hopewell people’s knowledge of geometry and astronomy.
A remarkable achievement in earthen construction by hunter-gatherers more than 3000 years ago.
Five historical mission churches from the Spanish colonial period in Texas.
An enormous cave system containing intricate rock formations that demonstrate. millions of years of geological processes.
Well-preserved prehistoric architecture that also demonstrates ancient Puebloans’ knowledge of astronomy.
A large and beautiful park containing mountains, old-growth forests, temperate rainforests and beaches.
A large protected area of great scenic beauty and species diversity.
The largest and earliest pre-Columbian city in North America.
Ruins of ancient cliff dwellings used over a thousand years ago by Ancestral Pueblo people.
A natural cave complex with extensive and varied rock formations.
Four nature reserves that combine to protect the oldest and tallest trees in the world.
Two active volcanoes and a protected habitat for endemic flora and fauna.
A vast gorge cut over the ages by the Colorado River, revealing 2 billion years of geologic history.
Colonial-era structures that demonstrate defensive architecture as it was adapted from European designs for a tropical environment.
Spectacular scenery and a showcase for the importance of international cooperation in protecting our planet’s wilderness.
A vast nature preserve hosting many species that once roamed North America, as well as a large number of active geothermal sites.
A vast wilderness of water and grass, habitat for many species, including endangered.
A potent symbol for Americans and the world, representing freedom and democracy.
Bedrock eroded by glaciers makes for an exceptionally beautiful natural environment of cliffs, sequoia groves, waterfalls and meadows.
Considered the birthplace of the United States, where both the Declaration of Independence and the Constitution were signed.