You should have waited another month. This weekend is going to be very cold.
Check out the Dequindre Cut, the new Riverwalk and state park. There's a ton of crap to see in Midtown. They have that green alley, the midtown loop, tons of new businesses, the new student housing, etc. Check out the revamped DIA. (BTW, I don't know how long it's been since you left, so I don't know what is "new" to you.
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