This story originally aired on October 28, 2017.
Near the coast of Washington state, on the banks of the Copalis River, lies a ghost forest -- a stand of gray, dead trees in the middle of a healthy forest.
How did it get there?
Could the key lie in another mystery, a mysterious tsunami recorded by samurai in 18th-century Japan?
Linking these seemingly unconnected phenomena became a goal for ambitious scientists using everything at their disposal, from computer models to chainsaws.