The best remaining testimony to Seljuq power at Merv is the 38m-high Mausoleum of Sultan Sanjar, located in what was the centre of Sultan Kala. The building was restored with Turkish aid and rises dramatically in the open plain.

　　Sanjar, grandson of Alp-Arslan, died in 1157, reputedly of a broken heart when, after escaping from captivity in Khiva, he came home to find that his beloved Merv had been pillaged by Turkic nomads.

　　The mausoleum is a simple cube with a barrel-mounted dome on top. Originally it had a magnificent turquoise-tiled outer dome, said to be visible from a day’s ride away, but that is long gone. Interior decoration is sparse, though restoration has brought back the blue-and-red frieze in the upper gallery. Inside is Sanjar’s simple stone ‘tomb’ although, fearing grave robbers, he was actually buried elsewhere in an unknown location. The name of the architect, Mohammed Ibn Aziz of Serakhs, is etched into the upper part of the east wall. According to lore, the sultan had his architect executed to prevent him from designing a building to rival this one.