Gibraltar is connected to Spain by a sandy isthmus, a ferry to Morocco and flights to London. The subject of repeated conquest and sieges, Gibraltar has been a British Territory since 1704. Ceded forever to Britain by Spain in the Treaty of Utrecht (1713), Gibraltar joined the EU in 1973, under the British Treaty of Accession. The locally elected Government of Gibraltar has created a solid economy. In a modern Europe, this country has its base in offshore finance, shipping, tourism and the Internet rather than its military past. There is, however, much of that for the tourist to see, along with the famous apes. When you first see the Rock of Gibraltar, it is its impressive stature, towering isolated above the surrounding countryside that has the greatest impact. It is a narrow peninsula linked to the end of the Iberian Peninsula by a narrow sandy isthmus. The Airport is built on this flat area, and the frontier with Spain is to the North. The Eastern side is made up of sheer cliffs, reaching a maximum altitude of 426 meters with sandy beaches forming the perimeter. The western slopes are gentler and much of its lower half is taken up by the city, with the upper parts having been turned into a nature reserve.