Spain is located in southwestern Europe and comprises most of the Iberian Peninsula. Its geography is diverse, containing mountainous regions, coastal plains, and inland plateaus. The climate also varies significantly from region to region. Historically, Spain established a vast colonial empire beginning in the 15th century and became one of the world's leading economic and military powers under the Habsburg monarchy. However, the country entered a period of decline in the 17th century following several military defeats. Today, Spain has a largely service-based economy and is a member of the European Union.