Volcanic lakes form when water collects in the craters of extinct volcanoes. Poas Volcano in Costa Rica, <I>shown,</I> contains a volcanic lake in one of its craters.
<BR><P>
Thomas Hollyman, Photo Researchers</P>
</BODY></P>
<!-- <PT>YES -->
<!-- <AR>From The World Book Multimedia Encyclopedia (TM) (c) «date» World Book, Inc., 525 W. Monroe, Chicago, IL 60661. All rights reserved. -->