What's the first thing you might notice about the British Museum? It's humongous! The museum map at first glance is bigger than my hand and longer than an octave on a piano (how far my hand stretches lengthwise), then proceeds to fold out to almost three times that size. And that's a bare minimum map, with small print correlating to numbered exhibits so as to take up the smallest amount of space possible. I actually didn't end up using the map very much at all, because it was easier to just wander and see what you found.
I spent almost an entire day in the museum, managed to see most things, and only sat down for about 10 minutes while in there. Well, 20 minutes, if you want to count when I stopped for lunch in a cafeteria corner of the Great Hall, pictured here courtesy of Wikipedia.