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

View of cruise ship in port and terrakotta rooftops in Alfama, Alfama District, Lisbon, Portugal, Europe

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

In the foreground signpost to the pass summit of the highest navigable alpine pass Col de l'Iseran 2764 2770 metres high, Iseran Pass, Iseran, below direction signs to Lanslebourg and Bourg Saint Maurice, in the background chapel Chapelle Notre-Dame-de-Toute-Prudence, Col de l'Iseran, departmental road D902, Route des Grandes Alpes, Département Savoie, Region Auvergne-Rhône-Alpes, Graian Alps, France

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