Ulugbek was not only a ruler, he was an astronomer as well. This represented one of the great archaeological finds of the 20th century. His 30m astrolab was part of a three stories tall observatory he had constructed in the 1420's. Nothing remains of the observatory, except for the astrolab's curved track, which was unearthed in 1908. There is an on-site museum containing miniatures of Ulugbek and his instruments.