Boat navigable part of the Coco River before it narrows into the Somoto Canyon National Monument, Somoto, Madriz, Nicaragua, Central America

Boat navigable part of the Coco River before it narrows into the Somoto Canyon National Monument, Somoto, Madriz, Nicaragua, Central America

Boat navigable part of the Coco River before it narrows into the Somoto Canyon National Monument, Somoto, Madriz, Nicaragua, Central America

Boat navigable part of the Coco River before it narrows into the Somoto Canyon National Monument, Somoto, Madriz, Nicaragua, Central America

Young guide-card salesman on board a tourist boat heading towards the Temple of Isis, Temple of Philae, Agilkia Island, Aswan, Egypt, North Africa, Africa

Tourists in paddle boat at entrance to Riverine Cave. longest navigable river traversed tunnel in the world, Subterranean River National Park, Sabang Town, Palawan, Philippines, Southeast Asia, Asia

Water front houses in Barrow upon Soar in Leicestershire, next to the river Soar.

Port of Hamburg, high-rise building in Altona, Hamburg, Germany, Europe

Norderney sounding vessel in motion in front of Norddeich, special ship for surveying the navigable water in the Wadden Sea, Lower Saxony, Germany, Europe