Soltaniyeh is the name of a small town on the plain between Zanjan and Abhar, and it is the name of one of the great buildings of Persia. The domed mausoleum of Oljeitu, finished in about 1313, rises from the plateau to around fifty metres, with a diameter of about twenty-five metres, making it the largest brick dome in the world at the time and a forerunner of the domes of Samarkand, Isfahan and even the Taj Mahal. It was listed by UNESCO in 2005, and when you see it from the highway, a pale turquoise-and-ochre bulk with eight slender minarets around its base, it looks too big for the landscape.
Oljeitu, or Öljeitü, was the Ilkhan, a Mongol ruler descended from Genghis Khan's grandson Hulagu, who governed Persia from the late thirteenth century. He is an intriguing figure, who tried several religions, including Buddhism and Christianity, before settling on Islam, first as a Sunni and later reportedly as a Shia, and he built the mausoleum possibly to house the remains of Imam Ali and Imam Husayn, a plan that was abandoned. After his death the building was used as his own tomb. The design uses a double-shell dome, a technical advance that influenced later Persian and Ottoman architecture.
Inside, the walls were covered with painted and tiled decoration, and parts of it survive, with geometric patterns, floral designs and calligraphy in bright colours. Galleries run around the upper levels, and visitors can climb to the top for a view of the plain. The restoration of recent decades has been extensive, and the exterior brick is cleaned and consolidated.
The road to it is simple, a short turn off the highway between Zanjan and Qazvin, through wheat fields and flat horizons. The land is high and open, and wind is a constant, so take care on exposed sections. Heavy trucks use the main road. The town of Soltaniyeh has a few shops and tea houses, but for fuel you should head to Abhar or Zanjan, each thirty to forty kilometres off. Foreign motorcyclists in Iran typically need paperwork such as a carnet and often a guide, so check current rules in advance. The best time is late spring or early autumn, when the light is clear and the ground is not baked or frozen.