The prehistoric earthworks of Poverty Point in Louisiana and a collection of Frank Lloyd Wright buildings across the United States will be nominated by Interior Secretary Ken Salazar for the United Nations World Heritage List, his office announced Wednesday.

The list, administered by the United Nations Educational, Scientific and Cultural Organization, recognizes cultural and natural sites that are considered to be universally important, such as the Grand Canyon in Arizona, the Great Barrier Reef in Australia and the Taj Mahal in India. The National Park Service, part of the Interior Department, manages most of the 21 World Heritage Sites in the United States.

Map of Poverty Point (Poverty Point State Historic Site)

Salazar identified Poverty Point as significant for its extensive collection of earthworks, built 3,100 to 3,700 years ago. The vast complex of structures included an integrated complex of earthen mounds, enormous concentric ridges, and a large plaza; it may be the largest hunter-gatherer settlement that ever existed, the Interior Department says.

The Frank Lloyd Wright portfolio comprises 11 “iconic, intact, innovative and influential” properties of the iconic architect’s more than 400 buildings, the Interior Department says. They span 60 years and include Wright’s two longtime homes with studios and schools, four residences he designed for others, two office complexes, a place of worship, a museum, and a governmental complex.

The 11 properties are:

— Taliesin, Spring Green, Wis.

— Taliesin West, Scottsdale, Ariz.

— Fallingwater, Mill Run, Pa.

— Hollyhock House, Los Angeles

— Frederick C. Robie House, Chicago

— Herbert and Katherine Jacobs House, Madison, Wis.

— Price Tower, Bartlesville, Okla.

— S.C. Johnson & Son, Inc., Administration Building and Research Tower, Racine, Wis.

— Unity Temple, Oak Park, Ill.

— Solomon R. Guggenheim Museum, New York

— Marin County Civic Center, San Rafael Calif.

Below are photos of some of the Frank Lloyd Wright sites.

Hollycock House (Courtesy of Frank Lloyd Wright Building Conservancy)

Guggenheim Museum (Courtesy of Solomon R. Guggenheim Museum)

Fallingwater (Courtesy of Western Pennsylvania Conservancy)

Marin County Civic Center (Scott Zimmerman/Courtesy of Frank Lloyd Wright Building Conservancy )

S.C. Johnson & Son headquarters (Mark Hertzberg/Courtesy of Frank Lloyd Wright Building Conservancy)

The final decision on inclusion on the list will be made by the UNESCO World Heritage Committee, composed of representatives from 21 nations and advised by the International Council on Monuments and Sites. The U.S. nominations will likely be formally nominated in 2013, for possible inclusion on the World Heritage List in 2014.

Which sites do you think should make the cut? Please let us know in the comments section below.