Chris H.
Yelp
This museum, on the Bowdoin College campus, is excellent and provides a close-up walkthrough of the history of the various Peary and MacMillan expeditions to attempt to reach the North Pole in the early 1900s. There are scores of authentic artifacts, pictures, film footage and major pieces of equipment from the expeditions (including a dog sledge that's about 10 feet long), along with excellent historical information about the explorers, the indigenous cultures with which they interacted, and the wildlife and weather conditions they encountered. Several of the more charismatic critters are taxidermied and look down upon you from above the display cases.
Moreover, the museum features special exhibitions; the one I saw was on representation of birds in indigenous culture, spirituality and artwork, and it was quite fascinating.
One particularly interesting part of the collection focused on Matthew Henson, an African-American member of the expeditions. They have a trading card of him! ("Trading card," you say? Yup...the Hassan Tobacco Company included trading cards of world famous explorers in cigarette packs in the early 1900s, much like baseball cards of the time.)
The museum is small and easy to get through at whatever pace you choose; admission is free but a donation is appreciated, and there's a gift shop with some nifty little things.