I have long held a theory that perhaps vikings once visited Alaska. If one reads the journal of Leif  Ericsson it mentions the following: A large lake (ancient Lake Ahtna, which was larger than Lake  Michigan?) an island with big bears (Kodiak?) a large river with a great many fish (Copper River?) anthracite coal (Katalla?) an island with flat rocks and petroglyphs ( (Wrangell Island?) Huge trees (Sitka spruce, etc?) an island with deer (Montague?) and so on. I have no idea if they really were here, but it's fun to speculate.