Kota Gede which is often called Sargede lies about five kilometers south east of Yogyakarta. In that cemetery complex one can still visit the cemetery of the Mataram kings like Sutowijoyo or Ngabei Loring Pasar, the founder of the Mataram Kingdom, who was then called Panembahan Senopati. There is also the unique tomb of Ki Ageng Mangir. He was Panembahan Senopati son in law and his enemy at the same time. His dead body was buried half inside of the special area for kings and his families, and half of his body was buried outside of the complex, there is a stone called " Watu Gilang ", a stone on which Panembahan Senopati smashed the head of Ki Ageng Mangir to dead.
Those who want to go inside the cemetery have to wear traditional clothes that one can hire at the place. Kota Gede Royal cemetery open on Monday at. 10.00 am - 12.00 am, and Friday at 01.30 pm. - 04.00 pm. In addition to the cemetery, there are also graceful gates, a pond full of Clarius Melanodermas and a yellow turtle. This turtle is hundred years of age and people believe it as a sacred miraculous turtle.
source by http://www.jogjatourism.com/html/imogiri.htm