"We descend from the bridge into the city."
Translation:De ponte in urbem descendimus.
You could say that; it might suggest, though, that you were on the way to the city, whereas "in urbem" seems to insist on the winding up inside the city.
In my opinion, this would have more importance if the verb were in the past tense: i.e., whether we went towards the city (ad urbem), versus going all the way into it (in urbem), would be more of an issue. (If it were in the past, then we could say that it had happened one way or the other.)