The Nima Sand Museum was opened to the public on March 3,1991. It consists of a cluster of six glass pyramids. The largest of these is 21 meters high and and rests on a base whose four sides are each 17 meter long. Inside this main pyramid stands the world's largest hourglass: 5 meters high and 1 meter in diameter. One ton of sand flows through this hour-glass. This so-called sand calender is carefully turned over by a group of townspeople at twelve midnight on the last day of each year. It takes exactly one year for all the sand to flow through.