In North America, ancient Native American left behind some 50 medicine wheels, puzzling stone circles. They built the Big Horn Medicine Wheel, in Wyoming, about 600 years ago.
It features 28 spokes of rocks radiating from a large pile of rocks in the center. Around the rim of the wheel are six more piles, with one much farther out than others. A line drawn from the farthest rock pile through its center will point straight toward the sunrise of the summer solstice. Lines drawn through three other piles mark the rising points of the stars Rigel, Sirius and Aldebaran. Native Americans may have tracked the stars so that they could predict the change of seasons. For some this may have meant that it was time to relocate. Summer solstice marks the time when tribes celebrate summer’s arrival: They pray for rain and abundant crops.
