When the time is right, salmon travel back to their birthplace to lay and fertilize their eggs. It can be a long and tiring journey and sometimes manmade dams get in the way.
To help the fish out, wildlife experts build fish ladders. The fish are able to leap from one level of the ladder to the next. Think of it like miniature swimming pools with each pool a little bit further up than the next. The salmon are eventually able to leap their way past the dam and continue on their way.
A fish ladder in Sweden helps fish get past a steep waterfall. [lmfoto / Shutterstock]
