US2 - Ships in a Busy Harbour

A city's harbor is one of its busiest locations. There are always ships moving across the water. A couple of tugboats are moored next to a speedboat, and a large shipping barge is bringing containers into port. What do you think is in the shipping containers? A cruise liner is heading out to sea, and an oil rig can be spotted out in the water too. Is that a military vessel out on the horizon?