I'm traveling through Detroit, what is there to do? My wife's cousin lives there, and she keeps saying there's tons to do, but then not telling me anything. I have 48 in Detroit with no plans. Any suggestions? I love museums, farmers markets, you name it.
It's not in the city, but if you have a car go to Dearborn and check out the Ford Rouge Factory Tour - it is fantastic. Henry Ford Museum is great as well - lots of great historical items (Abe Lincoln's bloody chair, Rosa Parks Bus, old cars, lots of trains, etc).
DIA, Historical Museum, and the Science center are all right down town and within walking distance of each other. Also if you like beer there is a bunch of really good breweries in the area
This is kind of random but there's a lot of pretty cool saltwater aquarium shops.... Tropicorium is one of my favorites, it's kind of like going to the aquarium but no charge! Plus its right by the airport