Here's one I've gone through and feel is a rather dangerous one: https://maps.app.goo.gl/pU36XG6J89QL2nqJA
The view is from top of the underpass, but if you look to the back left you can see there's a downhill and then a really sharp 90° turn which might lead to really dangerous situations due to poor visibility and high speed.
That underpass is just after a bridge (over the river) so they couldn't make it less steep by making the ramp longer, but the cyclists (those that know the area) can turn on the right right before the ramp and use the "normal" roads/streets, someone that isn't already familiar with it is taken by surprise.
This view from a bit further renders a little better the situation:
https://www.google.it/maps/@43.7752485,11.2348264,3a,75y,22....
A good example of how NOT to design an underpass (very steep AND curve in the middle), this is Florence (Italy):
https://www.google.it/maps/@43.7754979,11.2351912,3a,75y,53....
But they did put on a sign to prevent pedestrians to access it, so the mugglers won't go hiding there ;).