The Russian language classifies light and dark shades of blue as separate colors—which comes in especially handy if you venture north to Saint Petersburg in midsummer. The seaport metropolis sits less than 500 miles outside the Arctic Circle, so at the height of summer, the twilit "blue hour" coveted by photographers lasts virtually all night long as the sun hovers just below the horizon. It"s a phenomenon also dubbed the "White Nights" and it usually lasts for around 80 days, starting in May and lasting until July.