▲Distinguished by UNESCO in 2015, this site encompasses a group of five frontier mission complexes built by Franciscan missionaries in the 18th century. The buildings are clustered along a stretch of the San Antonio River basin.

▲The site includes architectural and archaeological structures, residencies, churches, and granaries, all of which stand in remarkable condition.

▲One of two transboundary sites shared with Canada, this stunningly beautiful and pristine site comprises the world’s largest non-polar ice field and some of the world’s longest glaciers.

▲UNESCO also describes the region as a natural habitat for wildlife, particularly for grizzly bears, caribou, Dall sheep (a subspecies native to North America), and every species of Alaskan salmon.

▲Once a major center for the ancient Pueblo peoples, the park preserves one of the country’s most important pre-Columbian cultural and historical areas.

▲The evocative ruins, which date from between the 10th and 12th centuries, are the densest and most exceptional concentration of pueblos (villages) in the American Southwest.

▲Added to the list in 1979 but later placed on the List of World Heritage in Danger in 2010 due to a worrying loss of marine habitat and decline in marine species, the park nonetheless remains the largest designated tropical wilderness reserve in North America.

▲The reserve is renowned as a sanctuary for an extraordinary variety of birds, reptiles, and several threatened or protected species.

▲Declared a World Heritage Site in 1984, the statue – one of the most recognized monuments in the world – was a gift to the United States from the people of France.

▲Designed by French sculptor Frédéric Auguste Bartholdi (1834–1904) and built by Gustave Eiffel (1832–1923), the iconic structure was dedicated in 1886.

▲With over 390 miles of passageways, this is the longest cave system known in the world. It was declared a UNESCO World Heritage Site in 1981.

▲This revered Philadelphia landmark was designed by Andrew Hamilton (1676–1741) and completed in 1753.

▲It marks the site of the Second Continental Congress during which the Declaration of Independence was signed in 1776. The room this historic document was drawn up in has been carefully preserved for posterity.

▲UNESCO declared this park a World Heritage Site in 1981 due to its outstanding diversity of ecosystems and varied topography.

▲The park boasts four very distinctive regions: the Pacific coastline, alpine areas, the west side temperate rain forest, and the forests of the drier east side.

▲Sited in St. Clair County, this site once constituted the largest and most influential urban settlement in the Mississippian culture, a mound-building Native American civilization.

▲Active between the 7th and 15th centuries, the Mississippian culture developed advanced societies across much of what is now the Southeastern United States.

▲Monticello was the home of Thomas Jefferson, who also designed the early buildings that made up the University of Virginia in Charlottesville.

▲The standout structure among these 18th- and 19th-century buildings is The Rotunda, a half-scale model of the Pantheon in Rome.

▲One of the country’s great natural wonders, the park contains half of the world’s geothermal features including over 300 geysers. It’s also celebrated for its profusion of flora and fauna.

▲Distinguished as the first National Park in the United States, and the world, Yellowstone was recognized by UNESCO in 1978, one of the first World Heritage Sites established in North America.

▲Sited one mile north of the modern city of Taos, this cluster of ancient pueblo adobe dwellings was constructed in the 13th and 14th centuries. The pueblo was declared a World Heritage Site in 1992.

▲About 150 people live in the historic complex full-time. Interestingly, the north-side pueblo is believed to be one of the most photographed and painted structures in North America.

▲The dramatic volcanic landscape is constantly shifting and provides visitors to the park with a rare opportunity to witness Mother Nature at her bubbling, burping and lava-spewing best.

▲Set over the state’s West Carroll Parish, the vast prehistoric earthworks of the Poverty Point culture, the indigenous peoples who inhabited the region from about 2200 BC–700 BC, offer a fascinating glimpse into how a society could so totally transform a landscape.

▲Poverty Point may well be the largest hunter-gatherer settlement that has ever existed, though the original purposes of the earthworks have not been determined by archaeologists.

▲Perhaps the most intriguing of the communities attributed to the Pueblo peoples, the cliff dwellings located in Montezuma County were carved out of sandstone between the 6th and 12th centuries.

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Around 600 houses built in alcoves and rock overhangs line a canyon at heights in excess of 8,500 ft. Notable examples include Cliff Palace – the largest cliff dwelling in North America! Listed by UNESCO in 1978, this is one of the first World Heritage Sites declared in the US.

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Its vast, cathedral-like chambers and complex series of tunnels and labyrinths has earned this cave system its titular name – Mammoth.

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Offering a compelling insight into the birth of the Hawaiian Islands, the two volcanoes located on the island of Hawaii, Kīlauea and Mauna Loa, are among the most active in the world.

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There are currently 24 World Heritage Sites in the US listed by the United Nations Educational, Scientific and Cultural Organization (UNESCO), destinations that help define the country’s national identity. How many have you visited?

Here we've listed 15 sites for your convenience. Scroll through the gallery for our guide to the nation's heritage highlights.