A cluster of European cities within a five-hour train ride of London could become a unicorn factory to rival Silicon Valley, argues tech investor Saul Klein.

The German capital attracts talent from all over the world, and its startups are building endless AI-generated audio apps, virtual pet apps, and sensors for early wildfire detection.

The French capital has become the home of Europe's growing AI industry—but alongside giants like Mistral are startups building EV charging infrastructure and trying to revolutionize social media.

The Swiss financial capital might be most associated with fintech, but its startups are also focusing on medical robotics, AI-powered language learning, and the batteries of the future.

There are around 4,000 startups in Amsterdam—the best 10 are tackling forest fires, decarbonizing plastics, and building robot bricklayers.

The Portuguese capital's most exciting startups include a platform to help entrepreneurs get going, a smart punchbag, and the Uber of hair salons.

The Finnish capital's most exciting startups are building nuclear-powered heating networks, better weather forecasting tools, and an esports streaming platform that lets viewers bet on the outcome.

The Spanish capital is drawing talent from Latin America, and its eye-catching startups are working on smarter payments, eldercare, and an AI-powered virtual nurse.

The Irish capital's embrace of Big Tech is filtering through to its startups, who are building better tools for IT teams, AI content moderation tools, and RNA screening for herds of cattle.

The Swedish capital produced Skype, Spotify, Klarna, and Minecraft—its stars of the future are building fintech for businesses, gen AI for lawyers, and full-body health care scans.

The UK capital's most exciting startups showcase its strengths in biotechnology and artificial intelligence.