The largest mega-city in Europe that's bigger than Barcelona, Rome and Athens combined

As of 2025, Moscow has a population of more than 12.7 million. (Image: Getty)

Europe is home to some huge cities. There is London and Paris in the west, Athens, Rome and Barcelona further south, as well as Minsk and Warsaw further east. However, none of those are the continent's biggest mega-city. That title belongs to Moscow in Russia.

Some people think Moscow is in Asia, but it’s actually on the European side of Russia. The Ural Mountains are considered the natural border between Europe and Asia, and Moscow lies well to the west of them. which means it is firmly in Europe. As of 2025, Moscow has a population of more than 12.7 million, according to the World Population Review.

Moscow has grown fast over the last few decades. (Image: Getty)

People from all over Russia and former Soviet countries move there for work. (Image: Getty)

That means it’s bigger than Barcelona (5.5 million), Rome (4 million) and Athens (3 million) combined.

The city has grown fast over the last few decades. It’s the capital of Russia and the country’s main political, business and transport headquarters.

People from all over Russia and former Soviet countries move there for work, better services and more opportunities.

In 2012, Moscow expanded its boundaries and took in neighbouring towns, doubling its size.

The wider Moscow region is now believed to be home to more than 20 million people.

Moscow is home to many famous landmarks including St. Basil’s Cathedral. (Image: Getty)

The Moscow International Business Center. (Image: Getty)

The city is known for its large metro system, which millions of people use every day.

The Moscow Metro is one of the busiest in the world, and some of its stations look more like palaces than train stops, with chandeliers, marble and mosaics.

There are also many famous sights to see, including Red Square, the Kremlin, St Basil’s Cathedral, and the modern Moscow City towers.

The city also has parks, museums, theatres and plenty of shopping areas.

Everyday life in Moscow can be busy and relatively affordable. (Image: Getty)

Everyday life in Moscow can be busy and relatively affordable. There are street markets, cafés, public events and lots of green spaces across the city.

But the war in Ukraine has affected life in the capital. In the past year, there have been drone attacks, flight delays and tight security measures.

Some airports have been closed temporarily and people have been evacuated from buildings during alerts.

As a result, the UK Foreign Office strongly advises against all travel to Moscow and other parts of Russia following the country’s invasion of Ukraine.