A great circle, also known as an orthodrome or Riemannian circle, of a sphere is the intersection of the sphere and a plane which passes through the center point of the sphere, as opposed to a general circle of a sphere where the plane is not required to pass through the center. (A small circle is the intersection of the sphere and a plane which does not pass through the center.) Any diameter of any great circle coincides with a diameter of the sphere, and therefore all great circles have the same circumference as each other, and have the same center as the sphere. A great circle is the largest circle that can be drawn on any given sphere. Every circle in Euclidean space is a great circle of exactly one sphere.

For any two points on the surface of a sphere there is a great circle through the two points. The minor arc of a great circle between two points is the shortest surface-path between them. In this sense the minor arc is analogous to “straight lines” in spherical geometry. The length of the minor arc of a great circle is taken as the distance between two points on a surface of a sphere, namely the great-circle distance. The great circles are the geodesics of the sphere.

"Medicine man" or "medicine woman" are English terms used to describe traditional healers and spiritual leaders among Native American and other indigenous or aboriginal peoples. Anthropologists tend to prefer the term "shaman," a specific term for a spiritual mediator from the Tungusic peoples of Siberia.

The primary function of these "medicine elders" (who are not always male) is to secure the help of the spirit world, including the Great Spirit (Wakan Tanka in the language of the Lakota Sioux), for the benefit of the entire community.

Sometimes the help sought may be for the sake of healing disease, sometimes it may be for the sake of healing the psyche, sometimes the goal is to promote harmony between human groups or between humans & nature. So the term "medicine man/woman" is not entirely inappropriate, but it greatly oversimplifies and also skews the depiction of the people whose role in society complements that of the chief. These people are not the Native American equivalent of the Chinese "barefoot doctors", herbalists, nor of the emergency medical technicians who ride rescue vehicles.

Heȟáka Sápa (Black Elk) (December 1863-August 19, 1950) was a famous Wičháša Wakȟáŋ (Medicine Man or Holy Man) of the Oglala Lakota (Sioux). He was Heyoka and a second cousin of Crazy Horse.

Black Elk said that during his life, he had several visions in which he learned things that would help his people. In his "great vision," at the age of nine, he said he met the spirit that guided the universe and saw a great tree that symbolized the life of the earth and of the Indian people. He did not speak of this to anyone until he was much older, but his family apparently understood he was clairvoyant after his supposed "illness".

Black Elk was involved in several battles with the U.S. cavalry. He participated, at about the age of twelve, in the Battle of Little Big Horn of 1876, and was injured in the Wounded Knee Massacre in 1890.

In 1887, Black Elk traveled to England with Buffalo Bill's Wild West Show, an unpleasant experience he described in chapter 20 of Black Elk Speaks. On May 11, 1887, the troop put on a command performance for Queen Victoria, whom they called "Grandmother England." He also described being in the crowd at her Golden Jubilee. He and Red Shirt officiated Surrounded By the Enemy's funeral in London. The interment was at Brompton Cemetery.

Mounds State Park is a state park in Anderson, Indiana, featuring Native American heritage, and 10 ceremonial mounds built by the prehistoric Adena culture indigenous peoples of eastern North America, and also used centuries by later Hopewell culture inhabitants.

The largest earthwork, the "Great Mound", is believed to have been constructed around 160 BCE. The Great Mound is a circular earth enclosure with an internal ditch and south to southwest entrance. The earthworks measure 394 feet (120 m) across from bank to bank. The 9-foot-tall (2.7 m) embankment is 63 feet (19 m) wide at its base, and the ditch is 10.5 feet (3.2 m) deep and 60 feet (18 m) across at its top. The central platform is 138 feet (42 m) across and was occupied by a 4-foot-high (1.2 m) central mound 30 feet (9.1 m) in diameter. One particular mound at the Anderson Site has a sequence of clay platforms, each deliberately covered by a layer of ash.

In 1900, a series of strange misshapen skeletons were unearthed from similar mounds in nearby Alexandria, Indiana. This brought thousands of tourists from around the Mid-West. In 1910, several locals admitted to stealing chimpanzee skeletons from the nearby Muncie Zoo's monkey house. In 1915 the skeletons were sold to a local museum which burned down in 1919.