Gibraltar is a British overseas territory located on the southern end of the Iberian Peninsula at the entrance of the Mediterranean, overlooking the Strait of Gibraltar. The territory itself is a peninsula of 6.843 square km whose isthmus connects to the north with Spain. The Rock of Gibraltar is the major landmark of the region and gives its name to the densely populated area with city status, it is home to almost 30,000 Gibraltarians.
The sovereignty of Gibraltar is a major point of contention in Anglo-Spanish relations as Spain asserts a claim to the territory and seeks its return. Gibraltarians resoundingly rejected proposals for Spanish sovereignty in referenda held in 1967 and 2002. (source) Thank you Tim, Yenni and Tintin!