Many nations have a profound connection to the ocean. In the constant rhythm of the tides, waves and seasons coastal people find a metronome for their lives. But few coastal nations have enjoyed as intimate and symbiotic a relationship with the ocean as Portugal. For a small country in Southern Europe that is so regularly overlooked these days, Portugal has one of the proudest seafaring histories in the world. Starting in the 15th century, they built an empire by pioneering trade and colonial conquest across the treacherous and unexplored “Green Sea of Darkness”, as the Atlantic was called. They were able to exploit Brazil’s riches and trade exotic goods thanks to their nautical skills. Even the name Portugal, means “the land of the port”.

However, I didn't visit Portugal for a history lesson, as enthralling as their nautical past may be. I came to Portugal to test my surfing skills against some of the most powerful swells to pound the edge of the Atlantic Ocean. Portugal has long been the jewel in the crown of European surfing. It draws surfers from around the world to regions such as Ericeira, with its feast of big wave reefs, and Peniche – home to the legendary Supertubos, a wave whose name, like Hawaii's Pipeline, speaks for itself. The great thing about wave hunting in Portugal is all the best waves are concentrated in a 100km strip in the centre of the country.

If arriving by air it’s likely you’ll land at the capital city of Lisbon. Most of the city was completely destroyed in the great Earthquake of 1755, which killed tens of thousands of people under falling rubble and a devastating tidal wave that followed the quake. Today the city is a bustling cultural metropolis sprawled over hills surrounding its spectacular natural harbour, sprinkled with ornate fortresses that face the ocean.

The first port of call for surfers travelling north of Lisbon is Ericeira – a sleepy coastal region that overlooks the Atlantic from towering golden cliff tops. Old world windmills painted blue and white keep watch over the ocean, while mules and horses can still be found slowly working the fields in the midday heat. This is a very pastoral region, and with only one decent sandy beach in the area (Ribeira D'llhas) and minimal shopping facilities, you won't find hordes or tourists ruining the serenity. However, you will find the best surfers from Europe and around the world driving back and forth in beat-up station wagons and VW Kombis along a short coastal strip, feasting on a dozen bone-snapping reef breaks and point breaks. Places such as Coxos and Sao Lourenco can handle surf bigger than two story buildings. Ericeira is definitely an place for experienced surfers, but those without a death wish will enjoy watching the fearless take off on these watery mountains from the many perfect vantage points on the cliff sides above the surf.

Less than 50km north of Ericeira is a typically sleepy Portuguese fishing village called Peniche. Located on a narrow sandy peninsula, Peniche was an island until the 12th century and today is one of Portugal's primary fish producing towns. It's many seafood restaurants serve up the culinary bounty of the Atlantic Ocean at low prices. They specialise in the freshest and juiciest sardines in Europe (a traditional Portuguese favourite), but their mussels and oysters are also excellent. The centre of Peniche is encircled by a defensive wall, featuring distinctive miniature observation turrets, which gaze out to sea as they have done since the 15th century.

But Peniche's main attraction is its year-round top quality surf. Being located on a narrow peninsula means Peniche is exposed to swells from all directions. North facing beaches like Lagide and Baleal are almost never without a rideable wave, picking up swells pumped out from storms in the northern Atlantic. But it is when the south swells arrive the whole region really goes into a surfing frenzy, because everyone knows Supertubos will be serving up a mind-bending feast of super-hollow barrels.

Of course, labelling a wave as “legendary” is a dangerous call for any surfer. People immediately think you're exaggerating for the sake of a good story – like the way a fish always gets a larger with every telling of a fisherman's tale. But Supertubos is “legendary” in every sense of the word. Imagine a barrel like Hawaii's Pipeline – but breaking on sand instead of viciously shallow coral reef.

I had the privilege of surfing Supertubos on what hardened local surfers were calling “the swell of the year”. A massive groundswell had travelled across the entire Atlantic Ocean from the United States, produced by Hurricane Ivan, which caused mass destruction and killed 25 people in Florida during September 2004. And the waves exploding onto the shallow sandbar at Supertubos were every bit as life threatening as the hurricane which produced them. Some of the barrels were big enough to drive a truck through – triple overhead monsters that boomed like an oceanic jet engine as they chased you down the line. I saw four snapped surfboards in half an hour. I also saw my life flash before my eyes on more than one occasion as I pulled into monster waves. One mistake on waves like this could well be your last.

Once you've had your fill of perfect surf in Peniche, a 20km drive inland will bring you to the picturesque walled city of Obidos. Its long and lively history includes being occupied by the Moors for centuries, before returning to Christian hands and then suffering extensive damage in the great earthquake of 1755 before being completely restored. Today it is still possible to walk most of the way around the city's defensive walls, taking in incredible views both of the surrounding countryside and the imposing castle below. At the height of summer the tight cobbled streets of this ancient town are unimaginably squashed with tourists wandering between the boutique stores, gift shops and intimate restaurants. But in autumn the streets of Obidos are pleasantly empty and you can get a better feel of what life was like here hundreds of years ago, under the shadow of the castle walls.

The nearby town of Nazare hugs a curving strip of white sand on the edge of the Atlantic. High bowed fishing boats painted with colourful murals are a common sight along the shore. The most famous of Portugal's traditional boats are the Rabelos. They were used for centuries to transport port wine, which was once the nations' most important export. These flat-bottomed, square-rigged sailing vessels have become less common in recent years as more efficient means of transport have made them impractical. However in places such as Porto and Nazare you can still find meticulously painted and cared for Rabelos that are obviously their owner's pride and joy.

Portugal's ubiquitous sea fog is a perfect symbol of the nation's connection to the ocean. At times the sea literally has a physical hold over the land as unearthly fogs roll in from the Atlantic and engulf coastal areas for days at a time. The sun is blotted out, visibility is reduced to a few meters and throats are tickled with a palpable wall of suspended moisture. This fog reminds the Portuguese of how closely their fate is intertwined with the Atlantic and instils in them a humbling sense of awe at its power. Maybe it is these mysterious fogs that have kept Portugal hidden from all but the most curious travellers for so many years.