Iquitos is the largest city in the Peruvian rainforest, with a population of 370,962. It is the capital of Loreto Region and Maynas Province. It is generally considered the most populous city in the world that cannot be reached by road. Located on the Amazon River, it is a mere 106 m (348 ft) above sea level even though it is more than 3,000 km (1,864 mi) from the mouth of the Amazon at Belém in Brazil, on the Atlantic Ocean. It is situated 125 km (78 mi) downstream of the confluence of the Ucayali and Marañón rivers, the two main headwaters of the Amazon River. Iquitos has long been a major port in the Amazon Basin. It is surrounded by three rivers: the Nanay, the Itaya, and the Amazon. The city can be reached only by airplane or boat, with the exception of a road to Nauta, a small town roughly 100 km (62 mi) south. Ocean vessels of 3,000 tons or 9,000 tons and 5.5 metres (18 ft) draft can reach Iquitos from the Atlantic ocean, 3,600 kilometres (2,200 mi) away. Most travel within the city itself is via bus, motorcycle, or auto rickshaw (mototaxi, motocarro or motokar). Transportation to nearby towns often requires a river trip via peque-peque, a small public motorized boat. The climate is hot and humid, with an average relative humidity of 85%. The wet season lasts from around November to May, with the river reaching its highest point in May. The river is at its lowest in October.