A National Historic Landmark (NHL) is a building, site, structure, or object that is officially recognized by the United States government for its historical significance. Out of more than 80,000 places on the National Register of Historic Places only about 2,430 are NHLs.

A National Historic Landmark District (NHLD) is a historic district that has received similar recognition. The district may include contributing properties that are buildings, structures, sites or objects, and it may include non-contributing properties. Contributing properties may or may not also be separately listed.

Prior to 1935, efforts to preserve cultural heritage of national importance were made by piecemeal efforts of the United States Congress. In 1935 Congress passed the Historic Sites Act, which formally granted the Interior Secretary authority to formally record and organize historic properties, and to designate properties as having "national historical significance", and gave the National Park Service authority to administer historically significant federally-owned properties Over the following decades surveys such as the Historic American Building Survey amassed information about culturally and architecturally significant properties in a program known as the Historic Sites Survey. Most of the designations made under this legislation became National Historic Sites, although the very first designation, made December 20, 1935, was for the Jefferson National Expansion Memorial in St. Louis, Missouri. The first National Historic Site designation was made for the Salem Maritime National Historic Site on March 17, 1938.

A historic site is an official location where pieces of political, military or social history have been preserved. Historic sites are usually protected by law, and many have recognized with the official national historic site status. A historic site is any building, landscape, site or structure that is of local, regional, or national significance.

Medicine wheels, or sacred hoops, were constructed by laying stones in a particular pattern on the ground. Most medicine wheels follow the basic pattern of having a center of stone(s), and surrounding that is an outer ring of stones with "spokes", or lines of rocks radiating from the center. Some ancient types of sacred architecture were built by laying stones on the surface of the ground in particular patterns common to aboriginal people.

Originally, medicine wheels are stone structures constructed by certain indigenous peoples of Africa for various astronomical, ritual, healing, and teaching purposes. Medicine wheels are still "opened" or inaugurated in Native American spirituality where they are more often referred to as "sacred hoops", which is the favored English rendering by some. There are various native words to describe the ancient forms and types of rock alignments. One teaching involves the description of the four directions.

More recently, syncretic, hybridized uses of medicine wheels, magic circles, and mandala sacred technology are employed in New Age, Wiccan, Pagan and other spiritual discourse throughout the World. The rite of the sacred hoop and medicine wheel differed and differs amongst indigenous traditions, as it now does between non-indigenous peoples, and between traditional and modernist variations. The essential nature of the rite common to these divergent traditions deserves further anthropological exploration as does an exegesis of their valence.