Built in 1420 for the Ming dynasty it is one of the largest Temple complexes in China. The Emperor, considered as the sun of Heaven, would pray and make sacrifices here. I couldn't find any info about what he actually sacrificed, just that it was serious business and it was up to him to provide a good harvest for the people.
When I was looking at other photos of the temple it seemed a bit dull to what I had seen. It was absolutely stunning. Then I read it had a 47 million yuan (5.9 million dollars) face lift for the 2008 Olympics. They're excited, now if they can just get people to keep there clothes on, yeah it's an issue.