The part of the world referred to as south-east Asia includes countries lying to the south of China, east of India and north of Australia. It is an area of high seismic and volcanic activity. South-east Asia consists of two distinct regions: mainland south-east Asia which includes the countries of Cambodia, Laos, Malaysia, Myanmar, Thailand and Viet Nam; and maritime south-east Asia which includes the surrounding island arcs and archipelagos that lie to the east and southeast - Brunei Darussalam, Indonesia, Philippines, Singapore and Timor-Leste. South-east Asia falls within the warm, humid tropics, and its climate is typically referred to as monsoonal, meaning that rainfall is high across the entire region, varying in relation to the monsoon winds. These conditions have led to the growth of the second largest rain forest on earth.