When Qazvin took its turn as Iran’s capital, this attractive, colonnaded cube was Shah Tahmasp’s royal palace . Built in 1510, it was greatly remodelled in the Qajar era. Set in the town’s little central park it looks especially photogenic at night, with its delicate balustrades floodlit and its back-lit coloured-glass windows glowing through the foliage. Inside is a calligraphy museum .