But one little-known, mysterious archaeological site does. The Kangjiashimenji Petroglyphs are bas-relief carvings in a massive red-basalt outcropping in the remote Xinjiang region of northwest China.
The artwork includes the earliest-and some of the most graphic-depictions of copulation in the world, the Huffington Post reported.
The petroglyphs - thought to date back to the second millennium BC, although their exact age is difficult to determine - were discovered in the late Eighties by Chinese archaeologist Wang Binghua.
Jeannine Davis-Kimball, an expert on Eurasian nomads, was the first Westerner to see them.
Though she wrote about the carvings in scholarly journals, they remain obscure. Google retrieves only a few results, depending on the spelling. The petroglyphs deserve more attention.
The cast of 100 figures presents what is obviously a fertility ritual (or several). They range in size from more than nine feet tall to just a few inches.
All perform the same ceremonial pose, holding their arms out and bent at the elbows. The right hand points up and the left hand points down, possibly to indicate earth and sky.
The few scholars who have studied the petroglyphs think that the larger-than-life hourglass figures that begin the tableau symbolize females. They have stylized triangular torsos, shapely hips and legs, and they wear conical headdresses with wispy decorations.
Male images are smaller triangles with stick legs and bare heads. Ithyphallic is archeology-talk for "erect penis," and nearly all of the males have one.
A third set of figures appear to be bisexual. Combining elements of males and females, they are ithyphallic but wear female headwear, a decoration on the chest, and sometimes a mask. They might be shamans.
The tableau is divided into four fully-developed scenes beginning at a height of 30 feet and progressing downward.
In the first scene, nine huge women and two much smaller men dance in a circle, seemingly admonishing their viewers. This is the only scene without ithyphallic men-though to the side, a prone bisexual has an obvious erection. Two symbols near the center look like stallions fighting head to head.
The second scene is packed with weird happenings. Women and men dance in a frenzy around a large ithyphallic bisexual about to penetrate a small hourglass female with an explicit vulva. His breastplate depicts a female head, with a conical headdress just like his. On the left, a second bisexual in a monkey mask is about to penetrate a small, faceless female. Nearby, a pair of striped animals lies prone amid bows and arrows, while at the other end, a giant two-headed female seems to lead the ritual. Disembodied heads abound, perhaps indicating spectators.
The next scene is smaller and cruder. A chorus line of infants emerges from a small female being penetrated simultaneously by a male and a bisexual while three more ithyphallic males await their turn. Another figure holds a penis longer than he is tall, pointing it at the sole large woman in the scene. She stands in front of a platform on which a faceless body lies prone, wearing what looks like the striped animals' fur. The body resembles the females copulating in this and the previous scene. It is the only figure shown with its arms lowered, probably indicating death in a ritual sacrifice. A small dog is also at the center.
The last full scene contains no obvious women at all, though the floating bodies on the upper right may be female. Ithyphallic males and a bisexual take part in a frenzied dance. One male seems to have his arm around another while a loner near the bottom seems to be masturbating as a parade of tiny infants streams from his erection. It looks a lot like a frat party.
There are four additional scenes that seem more like sketches. Two include a pair of dogs and another depicts male and female torsos with multiple heads. The last figure has a very long penis but the body of a woman and seems to be wearing a conical hat. It could be the artist, though no artist could have carved such a large, complex, and detailed tableau in a single prehistoric lifetime.
While Chinese scholars attribute them to nomadic cultures from 1000 BC, Davis-Kimball points out that nomads generally create portable art and not huge tableaus. The makers of the petroglyphs had to have been a sedentary people, since the elaborate artworks appear to have been carved over a period of centuries. This narrows the potential candidates down considerably. The only time in prehistory when sedentary people are known to have populated the region was during the Bronze Age, the millennium prior to 1000 BC.