Redwoods (2009) by Jason Chin.
This is one of the most creative non-fiction picture books I have seen yet. A boy in New York City hops on the F train reading a book on redwoods. When he climbs up the steps to exit the subway, he finds himself transported to the forests of California.
As you read, you learn more interesting facts about these ancient forests, all through the first-hand experiences of our main character. The illustrations bring the science alive. If only Jason Chin could have packaged up the smell of the redwoods, the transformation would be absolutely complete.