This is the Somerset Bridge in Bermuda - which is apparently the smallest working drawbridge in the world! Wikipedia says the bridge:

consists of two cantilevered half-spans, separated by a 32-inch (80 cm) gap bridged by a thick timber panel. The panel is removed whenever a yacht wishes to pass beneath the bridge, allowing the unsailed mast to pass through the gap.

Some dude at Princeton (who’s lucky enough to take family holidays in Bermuda) has a great river-level shot of this tiny sight.

Thanks to Sara.