It’s 10 P.M., the sun is high, and a swirl of college kids sip champagne on the banks of the wide Neva River. Three fortunate dudes in button-downs and nearly a dozen Russian beauties in cocktail dresses, clinging and revealing in all the right places, rotate in and out of a series of group selfies, which they then beam up to a satellite and into the social-media universe. And why not? They’re enjoying a perfect summer’s day in the middle of the St. Petersburg night, and they take a mean picture.

Just over the border from Finland, historic St. Petersburg is a UNESCO-certified jewel box of art, music and style. Summer is blessed with white nights and outdoor music festivals, and it’s the ideal time to explore the knot of gently arcing streets and 18th and 19th century apartment buildings with tarnished roofs that recall Montmartre. Sputnik Tours will get you onto the rooftops and inside the hidden courtyards you’d otherwise miss. It may be a touch Griswoldian, but you can also sightsee by canal if you hop on one of the many boat tours offered all over the old city.

Khochu Kharcho

No matter which way you cruise, you’ll glimpse massive cathedrals hewn from stone and crowned with gold, including the colorful Church of the Savior on Spilled Blood and St. Isaac’s Cathedral, which was built by 500,000 men and offers a rooftop colonnade with the best views in the city. In addition to touring the Hermitage, serious art fans should visit Erarta, an off-the-beaten-track, subversive modern art museum with an intriguing permanent collection and creative rotating exhibits featuring Russian artists. Cold war and military buffs will appreciate the Central Naval Museum, where they can view 300 years of Russian naval history, including the D-2 submarine Narodovolets, one of Russia’s first diesel subs.

The W St. Petersburg makes a fine base. Rooms offer sleek limestone entries, high ceilings, rain showers and blackout curtains (a summer must). The eighth-floor terrace enjoys magnificent sunset views over the city, St. Isaac’s and the Neva, and its in-house Mix restaurant, imagined by French celebrity chef Alain Ducasse, remains one of the best-reviewed spots in town. Or ditch the hotel and find one of the city’s excellent Georgian kitchens, such as Khochu Kharcho, where the meat dishes are perfectly prepared and the Georgian wine is a wonderful surprise.

The adventurous should hit the Dumskaya district after dinner. Sure, it’s hard-drinking, young and rowdy, and you should remain alert, but it’s also gritty in the best way, can be friendly and is often the gateway to a long, spectacular night. Fidel ($2 to $6 cover charge), a crumbling relic that rings with Cuban tunes, is the top option, but there are worthy alternatives.

Dom Beat

St. Petersburg loves its jazz, and the Hat is where impromptu jam sessions are the rule—except on Saturdays (weekends are for amateurs). It’s a hip and sophisticated scene and a perfect second stop before you hit the clubs. On to Dom Beat, which lures the best DJs in Europe, for its dance parties under mirror balls and ladies sipping bubbly in stilettos.