“Welcome on board. I have been tasked with taking you to Mäntsälä — in the middle of nowhere,” the minivan driver greets us in the characteristic clear and unhurried intonations of a Finnish native speaker.

Mäntsälä is, indeed, in the middle of nowhere. But this kind of location is often where you find collections of some of the most powerful machines of today, humming away behind doors along unpretentious corridors.

This includes Nebius' AI data centre, taking shape in the small community an hour's drive or so north of Helsinki.

Amsterdam-based Nebius is labelling itself an AI cloud infrastructure company. Its proprietary platform, it says, has been optimised for AI training and inference without performance bottlenecks.

“The AI cloud is different from the ‘regular' cloud. In the set of tools, in the applications, yes, but the people who use it are also different,” says Nebius' head of product and infrastructure, Andrey Korolenko.

The would-be European AI infrastructure force has begun amassing a tremendous amount of compute. Today, it announced that it will triple the Mäntsälä capacity to up to 60,000 Nvidia GPUs.

Precisely, this entails deployment of Nvidia's H200 GPUs, available from November, in addition to already installed H100s. Nebius is also one of the launch partners for Nvidia's upcoming Blackwell platform.

The Blackwell GB200 will enter mass production in December. Korolenko states that whenever the first unit ships (currently slated for Q1 2025), Nebius will also have it “in a matter of weeks.”

Filling gaps in the AI training and inference market

While others are toiling away to close the gap to Nvidia, the latter's hardware (along with its CUDA platform) is still the gold standard for AI training and inference. Nebius' core business is to offer time on its GPUs to everyone from app developers and companies optimising foundation models for their own businesses to AI model tuners and builders, from pre-training to inference, with different levels of support for different levels of skill.

The company has 400+ engineers in its employ, and customers already include the likes of Mistral AI, Genesis Therapeutics, Recraft, and Jetbrains.

Nebius has built custom racks for its Nvidia hardware. “We are doing it [building the data centre] from the ground up,” Korolenko says. “If you build it, you can just adjust it,” he adds, addressing the evolving nature of chips along with all the infrastructure requirements this entails.

During our visit, a large batch of racks has just arrived from the manufacturer in Taiwan, and Nebius crew are in the process of unpacking them from their boxes. At the mention of Taiwan, red flags concerning supply chains immediately pop up, and it is not long before the question of “What will happen to you in the event of a ‘reunification' in the South China Sea?” arises.

“What will happen to the world in this case?” Korolenko muses, sounding rather stoic.

The data centre also houses ISEG, which currently ranks as the 19th fastest supercomputer in the world, and the fastest commercially available in Europe. With 35.26 GFlops per watt-second, it has also made it to number 24 on the Green Top500 list.

One billion USD in European AI infrastructure

The build-out of Mäntsälä is part of a plan to splurge a total of $1bn across Europe by mid-2025, including opening an additional three data centres across the continent (as well as one in an as-of-yet undecided location in North America).

This includes a recent addition in Paris, a colocation deployment based at Equinix's PA10 campus. The site, located in the Saint-Denis district, has an urban farm on the roof, and heat from its servers was used to heat the Olympic pool during the 2024 summer games.

At its Mäntsälä data centre, Nebius provides heating for about 2,000 homes. A feature that, if replicable, makes the company's presence an attractive proposition for other remote locations eager to up their green credentials.

Nebius' data centre currently only utilises air to cool its servers. This will change with the addition of the later GPU models. What will not change is the amount of power that will go back towards heating the neighbouring town — the percentage, approximately 70%, may even increase when deploying a liquid cooling system. In fact, with the expansion, Nebius will export more heat than the village of Mäntsälä requires.

The Yandex legacy

You may wonder how come you have not heard of a company with 400 engineers able to get a hold of tens of thousands of highly coveted Nvidia GPUs up until now. Nebius recently emerged from the European remnants of Yandex (which had a long-term relationship with the GPU maker) following the company's high-profile divestment from Russia.

One of the things to come out of that laborious process, other than the Mäntsälä data centre, was a few billion dollars in cash. This is currently fueling the rollout of what could end up being a global force in AI infrastructure.

As a result of the legacy from Yandex, Nebius Group is listed on NASDAQ. The group also encompasses data business Toloka, upskilling edtech platform TripleTen, and autonomous driving technology unit Avride. However, its shares are not currently trading. Earlier this month, it announced it had enlisted Goldman Sachs as its financial advisor with a view to recommence trading further down the line.

Yandex founder Arkady Volozh is Nebius' CEO, who has publicly criticised Russia's war in Ukraine. However, along with the Mäntsälä data centre, Nebius has likely also inherited a certain degree of suspicion due to its origins. The company has moved its employees out of Russia, essentially evacuating thousands of people including whole families to locations outside of the country in 2022.

The company does not allow its employees to work from inside Russia should they go back and visit. It has also had to go through rigorous vetting from EU authorities to receive approval for the divestment deal.

Its execs, who had to leave behind what they had spent decades building, seem, perhaps understandably, tired of answering questions related to Russia while trying to build something new elsewhere. However, given the critical infrastructure nature of data centres, they might have to practise patience while they field such questions for some time to come.