The Twenty-One Balloons
by William Pène du Bois
Recommended Age: 10+
This 1948 Newbery Medal winner, illustrated by the author, is a colorful utopian tale about a stressed out, retired arithmetic professor (William Waterman Sherman) who decides to get away from it all, in a gigantic lighter-than-air balloon. Set in the 1880s, the heyday of ballooning, it culminates in the professor eyewitnessing the greatest explosion in recorded history: the self-destruction of the volcanic island of Krakatoa, somewhere between Java and Sumatra in what is now known as Indonesia.
In between his departure from San Francisco in the enormous, imaginative balloon "The Globe," and the big bang, he crash-lands on the island where he meets not natives, but American families who have settled on the island, in spite of its constant earthquakes, in order to enjoy the fabulous wealth of owning the world's largest diamond mine and the inventive society that unlimited wealth and complete secrecy makes possible. Professor Sherman learns about the "gourmet government," the "balloon merry-go-round," and all kinds of other outlandish inventions, before the whole population of the island (81 people, including the Professor) has to beat a hair-raising escape on a gigantic platform supported by 20 hydrogen balloons.
It's a humorous tale, full of colorful whimsies, wit, and charm, and I think you might get a kick out of the pictures too.
EDIT: Besides being a Newbery Medal-winning author, Pène du Bois was also a two-time Caldecott Medal-winning book illustrator. Wiki him for more info.