Archeology continues to be in the news with the announcement of the discovery of a possible "Amazon Stonehenge" in Brazil.
Archeologists say it could be an observatory/temple because the blocks are arranged in alignment with the winter solstice. The path of sunlight through the rocks could have possibly been to calculate time of year. This is evidence for a calendar. Scientists say the ruins, if they are ruins, are between 500 and 2,000 years old.
As one can tell from the picture, the Indians of the Amazon were better at astronomy than architecture. The possible ruins put the Indians on the same astronomical development with whoever built Stonehenge (constructed well before the Druids) and the Egyptian Pyramid makers- both who did their work around 4,500 years ago. However, while these Indians were just learning to cut stone into pretty patterns the Inca created roads, and the Maya and Aztecs made great cities and astronomical calendars.