WARNING: X-Men: The Last Stand Spoilers Ahead. Abandon hope, all ye who enter and have not seen the movie.
In the third act of X-Men: The Last Stand, metal morphin' mutant Magneto moves the Golden Gate Bridge from its original location to a new spot, where it connects Alcatraz to the mainland.
It's a super-fancy special effect, but I immediately wondered: would the bridge actually span that distance? I'm no engineer, so let's leave structural integrity issues aside.
I decided to ask Gmaps Pedometer. Here's the original path of the bridge, which is apparently about 1.7 km:
And here, roughly, is where Magneto plants the bridge. I picked the shortest distance I could find. I also ensured that the end of bridge would sit on solid ground, which might not be a requirement.
As you can see, that distance is apparently slightly more than 2 km. I suppose if you didn't mind starting off your walk to Alcatraz on one of the piers, you might be okay.
The official line from Wikipedia is that the bridge is 2.7 km, 'including approach'. Surely much of the approach is concrete, and Magneto probably couldn't move those bits.
More importantly, the distance between the spans is only 1.2 km. If I recall correctly, the bad guys walk off the bridge just past one such span. They clearly didn't bring all 2.7 km of the bridge with them. I suppose Magneto could have stretched the bridge so that it was long enough.