The Ulugh Beg Observatory, located in Samarkand, Uzbekistan, was built in the 1420s by the astronomer Ulugh Beg during the Timurid Empire. It was a hub for Islamic astronomers like Jamshid al-Kashi and Ali Qushji. The observatory featured a large quadrant device for measuring celestial bodies with remarkable accuracy. Despite its eventual decline and destruction after Ulugh Beg's assassination, the observatory's legacy lives on as a testament to medieval Islamic astronomy.