The Makli Necropolis lies on a plateau of the Makli Hill Range about 6 kilometers from Thatta and is believed to contain the ruins of over one million graves, making it one of the largest necropolises in the world. Tombs were built here during the Samma, Arghun, Tarkhan and Mughal periods. The graves at the site range from large and elaborate mausolea of many former rulers of the fourteenth to seventeenth centuries to simple white-washed structures from modern times.

The larger memorial structures at Makli fall into two categories, stone structures and brick structures. Earlier structures tend to be built of cut stone, many of local sandstone, and have carved stone designs. They take the form of canopied tombs standing on pillars built over a grave arranged on a platform.  Many later tombs are built entirely of brick, with only a stone plinth, and are covered in colored tiles, most of which have disappeared. However, stone monuments were built into the seventeenth century, and pre-Mughal brick structures exist as well.

The monuments at Makli were inscribed on the UNESCO World Heritage List in 1981.

Sources:

"Thattha." In The Grove Encyclopedia of Islamic Art and Architecture, edited by Bloom, Jonathan M., and Sheila S. Blair. : Oxford University Press, 2009. http://www.oxfordreference.com/view/10.1093/acref/9780195309911.001.0001/acref-9780195309911-e-918.

UNESCO. "Historical Monuments at Makli, Thatta." Accessed June 19, 2014. http://whc.unesco.org/en/list/143.