At 36,125 square kilometres (13,948 sq mi), the country is larger in size than Taiwan or Belgium. It lies at a low altitude; its highest point is 300 metres (984 ft). The terrain of is mostly low coastal plain with swamps of Guinean mangroves rising to Guinean forest-savanna mosaic in the east. Its monsoon-like rainy season alternates with periods of hot, dry harmattan winds blowing from the Sahara. The Bijagos Archipelago lies off of the mainland.

Guinea-Bissau is larger than what two countries?