No city in the world with a million or more inhabitants sits closer to the North Pole than Helsinki. Its extreme geographical location means that when days are short, they are very short, and when they are long, they are nearly endless.

On luxuriously long summer days, where do Finns go? Often it is Suomenlinna, a beautiful, compact archipelago just over a mile from Helsinki's busy harbor.

Known as "the Gibraltar of the North," Suomenlinna is a fortress-turned-community covering eight footprint-shaped, rocky islands. Fortress walls, bucolic parks and views of the sea make the place, with its warring history, a most peaceful place to relish Finland's capital.

Originally called Sveaborg, the fortress was designed by Swedish master architect Augustin Ehrensvärd, beginning in 1748.

You might ask, "Why did the Swedes build a fortress in Finland?"

For the answer, it's worth walking directly from the ferry pier to the middle of the fortress, past the sights along the way, to the visitor center, to see a film that traces Suomenlinna's history, comprehensible to all through choose-your-language headphones. Without that first step, one could amble around enjoying spectacular views out to sea without really understanding the fascinating and fraught history of the place.

A walk through Baltic history

Complex relationships of three main nationalities -- the Finns, Swedes and Russians -- intertwine here. For most of the fortress' existence, the three players were in a state of antagonism, if not out-and-out war. The periods of the area's history reflect the tension: the Swedish era, the Russian era and the Finnish garrison era.

It started when the Swedes decided to build a fortress on the eastern edge of their empire, i.e. on Finnish land, as a defense against Russia. To the 1,500 mostly impoverished residents of then-backwater Helsinki, Ehrensvärd's enormous construction project was an economic boon and the beginning of Helsinki's development as a major port city. The Swedes named the installation -- composed of 8 kilometers of 10-foot-thick stone walls, bastion towers, gatehouses, docks, interconnecting tunnels, and jetties -- Sveaborg.

From 1788 to 1790, Sveaborg was Sweden's principal base for military operations during the Russo-Swedish War. By 1808, the Swedes and Russians were at war again, this time for control of Finland. The year 1809 lives in infamy in the hearts of many a Swede. The commandant of Sveaborg, Carl Olof Cronstedt, surrendered his imposing, gun-packed fortress to the Russians after a three-month siege. In Cronstedt's defense, historians now say he had little choice in his decision, which turned Sveaborg into Russia's westernmost Baltic fortress, called Viapori.

Viapori remained in the thick of political tumult that raged throughout Europe during the next century. During the Crimean War in 1855, Viapori withstood a furious attack from French and English gunboats, and in 1906 it was the site of a military rebellion following revolutionary unrest in Russia. After the Bolshevik revolution of 1917, Russian Viapori became Suomenlinna, which means "Fortress of Finland." It was Finland's most important military asset until 1973, when the site became a national park.

Looking about at this cluster of rocky islands, the carefully hewn and positioned granite blocks and deeply entrenched bunkers, it's easy to understand why Suomenlinna was named a UNESCO World Heritage Site in 1991.

A day on Suomenlinna

Suomenlinna today is a pleasant day trip from Helsinki and one of Finland's most popular attractions. On the late-May day we were there, several school groups thronged, from Finland as well as other parts of the world. In addition, numerous European families were out for the day, along with a squad of young looking Finnish soldiers (there is still a naval academy located here) and clusters of Japanese tourists. But, the immense size of the fortress and the plenitude of paths and views meant we never felt crowded or hurried. At some sights and museums, we had the place to ourselves.

Suomenlinna has six museums, including a retired WWII submarine, a toy museum and a museum that traces Finland's rather checkered record of military engagements throughout the centuries. The Ehrensvärd Museum provides a bit of social history. Construction of the fortress took decades and military postings were so lengthy that, from its earliest years, Sveaborg was populated by the wives and children of builders and military personnel. Society life developed as sophisticated Swedish ladies moved to the archipelago outpost and did all they could to make it more like home.

Historical sites, too, are key to understanding this important cog in the wheel of northern European history. Augustin Ehrensvärd's tomb is one example. Called "the most beautiful tomb in Scandinavia," it was designed by Ehrensvärd's patron, Swedish King Gustav III, and cast from bronze melted down from captured Russian weapons. Gustav's piece depicts a sword, shield, scroll and helmet surrounded by wide-eyed cherubs who seem eternally surprised that the revered Ehrensvärd actually died.

We found the multipurpose, much remodeled Suomenlinnan Kirkko, or main church, particularly curious. Originally built in 1854, the Russian Orthodox garrison church was dedicated to Alexander Nevsky. After Finland gained its independence, the church was consecrated as a Lutheran church at Christmastime 1918, and its onion-dome cupolas were later replaced. In the 1960s the church steeple was fitted with a powerful navigation light, making it one of the few churches in the world that does double duty as a lighthouse. All night long, the light in the steeple blinks out "dot-dot-dot-dot," Morse code for the "H" in Helsinki.

Hunter's plate, Finnish fare

At rustic Bar Valimo, in a brick building that was once an ammunition foundry, we sipped coffee while planning the day's explorations. It is one of eight restaurants on Suomenlinna.

Bar Valimo's coffee concoctions are listed in Finnish on a chalkboard near the counter. English cognates helped us decipher all but one drink's name: Haudutetutee. The handsome proprietor laughed when we asked if it is a traditional Finnish drink.

"No, it's Chinese. You put the tea ball in a carafe of hot water and watch it open into a flower," he explained. "Try it; it's quite beautiful!"

Late in the day, as we headed back to the ferry pier, we craved more authentic flavors of Finland. We found them at the Jetty Barracks, which offered a nice end to our daylong retreat into Baltic history and windswept seascapes. The repurposed barracks now serves as a sort of village central, housing a pharmacy, post office and ice cream shop next door to an art gallery and a gastro pub.

We stopped by Suomenlinna Brewery Restaurant, which brews and serves a number of unfamiliar beers, including Höpken Pilsner, Spithead Bitter, and our favorite, the alcohol-rich Tin Soldiers Hard Cider.

As interesting as the beer selection was, the menu was even more so, offering locally sourced Finnish authenticity. We settled on the game zakuska, a charcuterie plate that featured reindeer liver paté, prosciutto-thin smoked reindeer, tangy bear salami, a wild boar rillette, delicate pickled chanterelles and cranberry sauce with juniper berries. Accompanied by a bountiful basket of sweet and savory breads and served with the sort of relaxed graciousness we experienced throughout Suomenlinna, it was the perfect bon voyage repast before we boarded the ferry to return to Helsinki.

As we hopped off the boat at the Helsinki quay, we saw a veritable small city of white-tent-topped vendor stalls, Helsinki's renowned waterfront Market Square. At 4:30 p.m., food vendors were working full tilt, serving queues of visitors as well as Finns leaving work and enjoying dinner al fresco. With nearly seven more hours of sunlight ahead, the day was still young-ish. And the Finns and their fans were intent on enjoying every minute of it.

Minneapolis-based writers William Gurstelle and Karen K. Hansen frequently collaborate on articles for national magazines such as Cruise Travel.