Canoes Locking through Lock and Dam #1 in Minneapolis, Minnesota. Locks raise and lower boats through dams on the Mississippi River. Locking through is free from the largest barges to the smallest canoes.
National Park Service
<a rel="nofollow" class="external free" href="http://www.nps.gov/miss/photosmultimedia/press_gallery.htm">http://www.nps.gov/miss/photosmultimedia/press_gallery.htm</a>