Malaysia Airlines flight MH370 disappeared off radar screens on March 8, 2014 while flying over an area where the Gulf of Thailand meets the South China Sea. Here are five things you need to know about the region:

1. The South China Sea covers about 3.68 million sq km, more than 5,000 times the size of Singapore. Its south-western part, including where the Gulf of Thailand lies, is a submerged plain where the water is generally shallow, less than 60m deep. But the largest marginal sea of the western Pacific has a mean depth of 1,060m and a maximum depth of 5,016m. Its deepest section is called the China Sea Basin.

2. There are over 250 small islands and reefs in the South China Sea and the region is subject to violent typhoons. But there was no bad weather report or distress call from the Malaysia Airlines plane before it lost contact with ground air control.

3. The South China Sea contains some of the world's most important shipping lanes. It also has rich fishing grounds and is believed to have potentially significant gas and oil deposits.

4. The area is a source of political tension, with simmering territorial disputes involving several countries. China has claimed sovereignty over most of the resource-rich South China Sea, including the Spratly and Paracel island chains. But Taiwan and Asean members Brunei, Malaysia, the Philippines and Vietnam have also laid claim to portions of the territories.

5. The Gulf of Thailand, which used to be called the Gulf of Siam, is an inlet of the South China Sea . It covers an area roughly 320,000 sq km in size. The gulf is relatively shallow. Its mean depth is about 40m; the western part is about 15m; and at its deepest, it is just 80m. There are many coral reefs in the Gulf of Thailand, making it a popular tourist destination for diving and beach holidays. Among the more popular tourist sites are Pattaya, and the islands of Koh Samui, Koh Tao and Koh Samet

Sources: Thailand's Department of Marine and Coastal Resources, CIA World Factbook, The Straits Times, Encyclopaedia Britannica