Don't make the mistake that I did when you go to Tiahuanaco/Tiwanaku. I saw the small sign for Puma Punku but did not stop. It has not been restored but contains one of the big mysteries of the ancient world. It is still not known how those massive stones were cut and moved with the technology available at the time. I certainly plan to stop there the next time I visit. The entrance is near where you turn to go to the museums right before you get to the village. In the picture, which was taken from the top of the Akapana mound, Puma Punku is in the background between the museums (on the left) and the mountains.
In the west face of the Sun Gate you will find all these carvings on the rock surface: messengers, warriors, Gods, snakes, condors, suns... it all seems to be part of a calendar related with agriculture and seasons.
If you take a guide, he will explain to you the meaning of all those figures. If not, just stand in front of the Gate and wait till the next group arrives, and you will share their speech!! :-)))
Puerta de la Luna stands by itself west of the Kalasasaya. The Gateway of the Moon is smaller and less elaborate than the Gateway of the Sun. However, it is also carved from a single stone and has animal designs on it.