The Netherlands, informally Holland, is a country in Northwestern Europe, with overseas territories in the Caribbean. It is the largest of the four constituent countries of the Kingdom of the Netherlands. The Netherlands consists of twelve provinces; it borders Germany to the east and Belgium to the south, with a North Sea coastline to the north and west. It shares maritime borders with the United Kingdom, Germany, and Belgium. The official language is Dutch, with West Frisian as a secondary official language in the province of Friesland. Dutch, English, and Papiamento are official in the Caribbean territories. People from the Netherlands are referred to as Dutch. Netherlands literally means "lower countries", in reference to its low elevation and flat topography, 26% of which is below sea level. Most of the areas below sea level, known as polders, are the result of land reclamation that began in the 14th century. In the Republican period, which began in 1588, the Netherlands entered a unique era of political, economic, and cultural greatness, ranked among the most powerful and influential in Europe and the world; this period is known as the Dutch Golden Age.