Lake Michigan

We traveled across the lake on a ferry that was huge enough to swallow the RV and a couple buses and some 18 wheelers along with a few car carriers without so much as a burp.  And that doesn't even count the dozens of cars they took aboard.
The trip took about 4.5 hours and we were entertained the whole way across, mostly by just standing along the rail  and watching the water slip by.  It was great fun.