As I explored Rimatara, I came across several incredible graveyards, filled with large, rounded gravestones, all mismatched and of various sizes and shapes. Many of the stones date back to the mid-1800s, and it is my assumption that the earliest dates on these gravestones correspond to the arrival of the first Christian missionaries in these islands.  The gravestones themselves are made from a material called coralstone, which is used to construct many of the buildings on the Australs.  Coralstone is made by heating coral to a high temperature until it becomes brittle and crumbles easily. This cooked coral is then crushed into a powder and mixed with sand and water to form a kind of cement that can be molded into building blocks, or gravestones.