City: Columbus, OH
You can take the boardwalk for a walk on the wild side in late spring: what makes it wild? slippery when wet. But if you get there after first snow, watch your step again lest slip and you miss your reward: a waterfall within the city limits.
Come back every week to watch as it turns to an ice-waterfall as winter's clutches transform it. In late summer it may slow to a single stream, but the shale walls and abundant vegetation make for a picturesque and enjoyable, albeit short, stroll.
If walking on the boardwalk isn't your thing, you can watch and listen from on high. Where is this anomaly of otherwise f-l-a-t Columbus? Run don't walk for the hills and you'll find it where you least expect to.
If you know this place, share with us how you discovered it or any other story about it.
I will happily reveal the trail name and location in a week or two if no one posts the right answer, and confirm the answer if anyone gets it right. I look forward to hearing from fellow urban adventurers.
Deadline (more for me than anyone else): Friday 11/15/13.