Bulgaria. Environment. Northern Bulgaria. The mountainous south.

Bulgaria, a mountainous land broken by fertile valleys and plains, is bordered to the north by Romania, to the west by Yugoslavia and Macedonia, and to the south by Greece and Turkey. The Black Sea lies to the east. Bulgaria's four main land regions are the Balkan Mountains, the Danubian Plateau, the Transitional Mountains and Lowlands, and the Rhodope Mountains. Because of the sharp contrasts in its terrain, Bulgaria's climate varies greatly from region to region.

The country's landscape is shaped chiefly by the Balkan Mountains, which stretch across Bulgaria from west to east, dividing the country in half. The northern half—the Danubian Plateau—has cold winters but warm and humid summers. The southern half—the Transitional Mountains and Lowlands—has cool winters and hot, dry summers.

In the mountain regions, weather conditions change yet again, depending on the altitude and the distance from the sea. The country's average rainfall is 25 inches (63 centimeters), and snowfall is light, except in the mountains. Near the Black Sea coast, winters are mild and summers are hot.

A small town occupies a sheltered valley in south-astern Bulgaria. The Maritsa and Tundzha river valleys support the cultivation of fruits and vegetables, such as apples, grapes, pears, tomatoes, and watermelons.

Northern Bulgaria. The Danubian Plateau, which covers northern Bulgaria from the Danube River south to the Balkan Mountains, is a vast sheet of limestone covered with river silt. As a result, this region has the country's most fertile farmland. The Danube River forms most of the border between Bulgaria and Romania, and several of its tributaries—including the Iskur and the Yantra — flow northward from the mountains.

The Danubian Plateau is partly flat, becoming more rolling as it approaches the foothills of the Balkans. In the valleys and flatter areas, where the climate is more humid, fruit, vegetables, and wine grapes flourish. The drier uplands are used for growing corn and wheat. In the northeast, the vast expanses of scrub grassland provide ideal pastures for sheep.

Rows of corn grow on the Danubian Plateau, in the region's fertile soil, aided by the humid summer conditions. In the southern part of Bulgaria, where the climate is drier, irrigation provides moisture for crops.

Most of the Balkan Mountains are not very high. The taller peaks lie mostly in the west, and some tower about 7,120 feet (2, 170 meters) along the border with Yugoslavia. Generally, the Balkans form lengthy ridges and small plateaus where sheep graze and forests grow. Many mountain passes allow traffic to flow easily between the Danubian Plateau and the mountain regions of southern Bulgaria.

Immediately south of the Balkan Mountains lie a number of lower mountain chains, known as the Sredna Gora. A zone of fertile basins, where roses and wine grapes are cultivated, lie between the Balkans and these lower chains. Bulgaria's capital city of Sofia is situated in one of these basins, at an altitude of 1,800 feet (550 meters).

The mountainous south. The Rhodope Mountains stretch across southern Bulgaria, forming a natural boundary with Greece. Evergreen forests and alpine meadows are a dominant feature of this landscape. Northwest of the Rhodope, in the Rila Mountains, stands the Rila Monastery, a historic shrine revered by all Bulgarians and now the site of a national museum. West of the Rhodope rise the peaks of the Pirin Moutains, where bears, wolves, and wildcats are found among the abundant wildlife.

Snow-capped peaks rise above the Rila Monastery, hidden away in the Rila Mountains of southwestern Bulgaria. Bulgaria's highest peak, Musala, rises 9,596 feet (2,925 meters) along the northern tip of the Rhodope Mountains.

On the Black Sea coast, sandy beaches are interspersed with dunes, rocky cliffs, and forest covered hills. The large coastal resorts of Varna and Burgas are known for their splendid beaches and parks. Broad expanses of reeds and water lilies mark the deltas of the Kamchiya and Ropotamo rivers, and farther north, monk seals bask on the rocks along the shore.

Bulgaria's coast extends about 175 miles (282kilometers) along the Black Sea. The nation's sandy beaches, sunny climate, and fascinating historical ruins draw vacationers from all over Europe. Bulgaria's leading Black Sea ports are Varna and Burgas.