tour boats share the bosphorus with plenty of commercial traffic. the narrow and strategic strait is a bottle neck busy with freighters, including lots of ukrainian and russian ships, since this is the only route from ports on the black sea out to the mediterranean. for more crowds and urban energy, you can join the million commuters who ferry over and back every day from the asian side of istanbul. ferries shuttle in and out from all directions as seas of locals make their daily half-hour intercontinental commute.