Among the earliest monuments of ancient India that have survived are the Buddhist stupas of Sanchi, situated on a hilltop less than 50 km away from Bhopal in Madhya Pradesh. They are a World Heritage Site. The most famous stupa is encircled by a railing cut by four exquisitely carved gateways facing the four directions of the compass. The carvings show a world where people and animals live together in happiness and plenty. Female tree spirits, symbols of fertility, were used as welcoming figures on the gateways. Lotus flowers were both a beautiful decoration and a religious symbol. The Buddha himself is depicted by symbols, such as the wheel, which represents his teaching, or by footprints or an empty throne. The Buddha is probably not shown because he asked his followers not to make images of him.