<p><strong>Whitecaps churn in the Atlantic off West Africa as an underwater <a href="http://environment.nationalgeographic.com/environment/natural-disasters/volcano-profile/">volcano</a> erupts off <a href="http://travel.nationalgeographic.com/travel/countries/spain-guide/">Spain</a>'s Canary Islands on Monday. </strong></p><p>(See <a href="http://traveler.nationalgeographic.com/2007/11/destinations-rated/africa-text/2">how the Canary Islands fared</a> in an independent ranking of island destinations.)</p><p>Since last week, the volcano has been spewing gas and fragments of smoking lava, staining the ocean surface green and brown, as seen above.</p><p>Spanish authorities have closed a port on <a href="http://maps.nationalgeographic.com/maps/map-machine#s=r&amp;c=27.690824359526715,%20-17.889862060546886&amp;z=9">Hierro island (map)</a>, ordered ships away from the island's village of La Restinga, and banned aircraft from flying over the island's southern tip, according to the AFP news service.</p><p>Six hundred residents living at the port were evacuated Tuesday.</p><p>(See <a href="http://news.nationalgeographic.com/news/2010/07/photogalleries/100715-giant-underwater-volcano-indonesia-kawio-barat-science-pictures/">"Pictures: Giant Undersea Volcano Revealed."</a>)</p>