The Balkans are made up of several countries in the south-eastern part of Europe. They stretch from Slovenia in the north to Greece and the European part of Turkey in the southeast. The region has been troubled by many conflicts and wars throughout the centuries. It has often been called the "Powder Keg of Europe" because conflicts and wars have started there. The countries that make up the Balkans are Greece, Albania, Macedonia, Bulgaria, Serbia, Montenegro, Bosnia Herzegovina. Sometimes parts of Croatia, and Slovenia as well as Romania are considered to belong to the Balkans. The Balkans are a mountainous region. The Dinaric Alps, the main mountain range, reach from Croatia to Greece along the Adriatic Sea. The Balkan Mountains are somewhat lower and extend from Serbia eastwards into Bulgaria. The southern section of the Carpathian Mountains reach into Romania and Serbia. The Danube, the region's main waterway, flows through many countries of the Balkans into the Black Sea. Its broad plains provide fertile fields for farming. Most of the Balkans have a harsh, continental climate with hot, dry summers and cold winters. The coastal regions are influenced by the Mediterranean Sea. The peninsula was once covered with many forests. However, over the centuries, they have been cut down to make room for settlements and agriculture. Most of them region's 80 million people are Slavs, who are divided into different ethnic groups. They live in Bulgaria, Serbia, Slovenia, Croatia, Bosnia and Herzegovina, Macedonia and Montenegro. Albanians, Greeks and Romanians do not belong to the Slavic population. The three large groups-Serbs, Croats and Bosnians-fought against each other for many years after the breakup of former Yugoslavia. The Balkans are also the crossroads of major religions. Roman Catholics live in in Slovenia and Croatia; Orthodox Christians populate Serbia, Bulgaria, Macedonia, Montenegro and Romania. Muslims live in large areas of Bosnia and Herzegovina, as well as Albania. Smaller groups, including Romani, are spread across all of the Balkans. The Balkans belong to the poorer regions of Europe. Only Romania, with large deposits of oil and gas, has important raw materials. A large part of the population makes their living through farming and raising animals. Because large parts of the Balkans were under Communist control for many decades, industries are not as highly developed as in Western or Central Europe. Tourism plays a major role along the Adriatic coast.