European politics saw very few regime changes, the major exception being Portugal, which experienced a republican revolution in 1910. However, tensions between working-class socialist parties, bourgeois liberal parties, and landed or aristocratic conservative parties did increase in many countries, and it has been claimed that profound political instability belied the calm surface of European politics in the era. In fact, militarism and international tensions grew considerably between 1897 and 1914, and the immediate prewar years were marked by a general armaments competition in Europe. Additionally, this era was one of massive overseas colonialism, known as the New Imperialism. The most famous portion of this imperial expansion was the Scramble for Africa.