South Asia: Physical Geography and Cultural Heritage

South Asia is defined by three great physical features. The Himalayas, the highest mountain range on Earth, form its northern wall, still rising today from the ongoing collision of the Indian and Eurasian tectonic plates. South of the mountains, the Indo-Gangetic Plain -- fed by the Indus and Ganges rivers -- is one of the most densely populated regions on Earth. Most of the region's life, especially its farming calendar, depends on the monsoon: seasonal winds that reverse direction, bringing a wet summer season that most agriculture relies on, followed by a dry winter.

South Asia is the birthplace of several major world religions. Hinduism developed over thousands of years with no single founder, making it the world's oldest continuously practiced major religion. Buddhism was founded by Siddhartha Gautama in the 5th century BCE in present-day Nepal/northern India. Sikhism was founded in the 15th century CE in the Punjab region. The region also has large Muslim populations, especially in Pakistan and Bangladesh. India's traditional caste system, a hereditary social hierarchy historically associated with Hindu society, is described here as a historical and social structure -- discrimination based on caste is now illegal in India, though its social effects persist in places. British colonial rule over the subcontinent, known as the Raj, ended in 1947 with independence and partition into India and Pakistan (with Bangladesh later separating from Pakistan in 1971), a division drawn largely along religious lines that triggered one of the largest mass migrations in human history.