When we toured Maine last year, Becki & I along with our friends Brad & Andrea walked the full 1 mile breakwater wall out to the Rockland Breakwater Light. When we finally arrived at the end, Brad realized his batteries were shot. Luckily I was there to snap alot of shots for both of us. Just think if that happened and you were alone, knowing you will probably never have a chance again to revisit it!. Always keep some spares with you.
-RodW
