Ulugh Beg Observatory is one of the most significant medieval astronomical observatories, built by the scholar-prince Ulugh Beg, grandson of Timur, in the 1420s. The observatory housed a giant sextant with a 40-meter radius, the largest astronomical instrument of its time. Ulugh Beg produced a star catalog of over 1,000 stars with remarkable accuracy that remained unsurpassed for 200 years. The observatory was destroyed in 1449 and rediscovered in 1908. The on-site museum displays models and copies of star charts that revolutionized medieval astronomy.