Firozabad, the fifth city of Delhi, was built by Feroz Shah Tughlaq in 1354, the first city here to be built on the river. Only the fortress remains, with crumbling walls protecting the Jama Masjid (Friday mosque), a baoli (step-well), and the pyramid-like Hawa Mahal, topped by a 13m-high sandstone Ashoka Pillar inscribed with 3rd-century-BC Buddhist edicts. There’s an otherworldly atmosphere to the ruins.

On Thursday afternoon, crowds gather at the mosque to light candles and incense and leave bowls of milk to appease Delhi’s djinns (invisible spirits), who are said to occupy the underground chambers beneath the mosque. Shoes should be removed when entering the mosque and Hawa Mahal.