North India is a loosely defined region consisting of the northern part of India. The dominant geographical features of North India are the Indus-Gangetic Plain and the Himalayas, which demarcate the region from the Tibetan Plateau and Central Asia. North India has been the historical centre of the Maurya, Gupta, Pala, Harsha, Mughal, Sur, Maratha, Sikh and British Indian Empires. It has a diverse culture, and includes the Hindu pilgrimage centers of Char Dham, Haridwar, Varanasi, Ayodhya, Mathura, Vaishno Devi and Pushkar, the Buddhist pilgrimage centers of Bodh Gaya, Sarnath and Kushinagar, the Sikh Golden Temple as well as world heritage sites such as the Nanda Devi Biosphere Reserve, Khajuraho temples, Hill Forts of Rajasthan, Jantar Mantar (Jaipur), Bhimbetka Caves, Sanchi monuments, Qutb Minar, Red Fort, Agra Fort, Fatehpur Sikri and the Taj Mahal. Hindi is the lingua franca of North India and has an official status together with English.