Military helicopter hovers in clearing in Ulu Temburong National Park, Brunei

Military helicopter hovers in clearing in Ulu Temburong National Park, Brunei

Combine harvester in a wheat field, Herefordshire, England, United Kingdom

Combine harvester in a wheat field, Herefordshire, England, United Kingdom

Combine harvester in a wheat field, Herefordshire, England, United Kingdom

Helicopter from aircraft carrier USS Nimitz, Los Angeles, United States.

Helicopter from USS Nimitz, Los Angeles, United States.

Presidential helicopter leaves London with George W Bush on board after his official visit to Britain

Revolving blades of a 2.3 megawatt wind turbine, Blacklaw Windfarm, South Lanarkshire, Scotland

Revolving blades of a 2.3 megawatt wind turbine, Blacklaw Windfarm, South Lanarkshire, Scotland

Alternative energy source: wind turbines and a canola field