The Heimskringla is a remarkably good read. It’s a history of the kings of various bits of Scandinavia, from Oðin’s time up to the author’s present day, in the late 11th century. But despite being a medieval text, it’s just plain fun to read, and Snorri Sturluson (the author, one of the great scholars and politicians of his day, and possessor of a great-sounding name) does his best to give a real scholarly analysis, especially of the parts of the history that are furthest in the past and so hardest to verify. It’s got a very modern feel to it.
Besides, any history book with chapter titles like “King Fjolnir Drowns in a Mead Vat” can’t be that bad.