A construction worker examines the 'Echolot' (sonar), a giant wooden pavilion during the official press preview for the yearly German horticultural show 'Bundesgartenschau 2011' in Koblenz, Germany, on April 7. The ground plan of the wooden construction is derived from the oscillogram curve of the sonar of a local bat, the so-called 'evening sailor,' by architecture students of the western German city at the junction of the river Moselle and Rhine. The garden show opened its gates on April 15 and runs till October 16.

Wolfgang Rattay/Reuters