Polling stations open in Caracas as Venezuela presses ahead with a referendum that it hopes will strengthen its century-old claim to the oil-rich Essequibo territory controlled by neighbouring Guyana. Caracas contends that the Essequibo River to the east of the region is the natural border between the two countries, as declared in 1777 under Spanish rule, and that the United Kingdom wrongly appropriated Venezuelan lands in the 19th century. Guyana, however, asserts that the border was set in the British colonial era and was confirmed in 1899 by a court of arbitration. It says the International Court of Justice (ICJ), the UN's top judicial body, has validated this finding. IMAGES