Just three hours (and one minute) from St Pancras station, an often overlooked European city is becoming a lot easier to discover. Long beloved by architects (and their fans), but less well-known by most tourists, Rotterdam is finally stepping out of Amsterdam’s shadow.

With new direct Eurostar trains to the Netherlands’ two biggest cities, it’s Rotterdam which will benefit most from the new route — Amsterdam, with its legions of fans, is already painless to visit by plane.

This port — with its nickname of Manhattan an der Maas — was the starting point for many Jews who emigrated to New York; the art nouveau Hotel New York, former HQ of the Holland America Line, is one of the pre-war buildings which survived the Second World War, along with Tuin van Noord, a former canalside prison being transformed into luxury apartments.

But with much of the city razed to the ground, the war’s legacy is a city of futuristic architecture. Rotterdam’s centre, rebuilt 70 years ago, has matured into a stately spread of broad boulevards punctuated by fine Modernist buildings, presided over by an iconic monumental sculpture by Naum Gabo.

Like a huge stylised marble-clad tree stretching several storeys towards the sky in front of the de Bijenkorf department store, it’s the unofficial symbol of the reconstructed city and affectionately dubbed by locals “the Thing”.

While most of the 21st century architectural initiatives which make Rotterdam so exciting lie outside the city centre, one notable exception is the market hall with its fabulous vaulted ceiling whose psychedelic “Horn of Plenty” mural has seen the building nicknamed Holland’s Sistine Chapel. Below lies every kind of Dutch delicacy, with coffee stalls to sit while nibbling chocolate and people-watching.

An efficient Metro links the market hall and other highlights of downtown — including the Boijmans van Beuningen art museum, whose Mad About Surrealism show running until May looks like a treat — with outlying areas, many well worth a trip.

These include the Industriegebouw, a 1950s industrial complex reinvigorated by Rotterdam’s most famous resident architects, MVRDV, who also created the market hall.

Their own offices are here as well as a clutch of trendy dining spots and the concept store Groos selling products made only by designers living in Rotterdam — this hub of eclectic shopping delights has some very different souvenirs, from eye-catching socks to stylish homewares.

Or head west to discover the Blue House, by MVRDV founder Winy Maas. The rooftop extension to a family home in the suburbs led to a string of rooftop initiatives as ways of maximising living space in the city and circumventing flooding. Subsidies are now available for all who plant the rooftops of buildings, creating essential greenery to soak up the plentiful rain.

The Blue House itself is an enchanting pair of small houses forming en-suite bedrooms for a family of four who once slept as well as lived in the huge studio on the floor below — and is usually one of the private spaces which opens to the public for Rotterdam Rooftop Days at the beginning of June, revealing the high-level city hidden the rest of the year from public gaze.

One rooftop which you can enjoy year round is Op Het Dak, an urban farm with a cafe and one of the most uplifting places in town to enjoy a meal. With its menus focused on produce freshly picked from the terrace, the vegetarian and fish dishes also make it a haven for observant diners.

For Rotterdam’s most futuristic face, head to Wilhelmina to discover De Rotterdam. This iconic assembly of three linked towers by legendary Dutch architect Rem Koolhaas appear to be crazily teetering on their perches.

It’s also home to the ultra-hip Nhow Hotel, a well-priced base packed with visual treats from the lobby to the indoor-outdoor bar overlooking the water and bright, fun compact rooms.

Just a couple of Metro stops from downtown, it’s also easy walking distance of the revitalised dining and entertainment area, Katendrecht, the city’s former Chinatown, and will be close to Recycled Park, due to open later this year.

The enterprising vision of architect Ramon Knoestr, this floating park with plant-growing nurseries has been created from the tons of plastic debris dredged up from the harbour over several years.

Ambitious and creative, it’s a project which could only be dreamed up in water-bound, reinvention-obsessed Rotterdam — which will also be home to a Floating Farm later this year, on which cows can graze surrounded by water.

And if Rotterdam’s canals are a world away from the elegant 17th century houses found in its better-known sister, you can get a taste of this attractively Dutch world in The Hague, with its art museums and palaces less than 30 minutes away.

In this city once called the Gateway to Europe, this new age of the train ensures the gates are finally opening to Rotterdam.