The pyramids of Dashur, south of Saqqara, are from a period between the Step Pyramid of Zoser and the "true" pyramids of Giza. The bent pyramid got its name from the angle of its construction; it begins at an angle of 54 degrees, then is corrected to a more stable 43 degrees about 160 feet above the ground. This early experiment led to a more stable design, first implemented at the nearby red pyramid. This ideal angle was then applied in Giza to great success. Around these two well-preserved specimens are a number of 12th Dynasty ruins, largely mud-brick pyramids now in rubble. This site was closed for many years, as it is next to a military base. It remains rather obscure, with many fewer visitors (and much less mercantile chaos) than Saqqara and Giza to the north. The climb inside the red pyramid leads to three chambers, with vaulted passages similar to those of the Great Pyramid. The vaulting is perfect, creating a forced perspective effect.