Finland

When a long-awaited rail link opens between northern Finland and Sweden, it will be possible to travel some 5,000km by train from Portugal's Algarve to Kolari in Lapland – Finland's northernmost station.

"The grand opening of this route will hopefully be just before Midsummer in late June," Sampo Kangastalo, development director of the northern Finnish city of Tornio, tells Yle News.

A deal signed on Friday between the two countries aims to unlock the missing link plugging Finland into the European rail network: a short distance between stations in the twin border towns of Tornio and Haparanda, which for decades has only been possible by bus or car.

Opening that bottleneck has required many years of bureaucratic and budget wrangling as well as electrification of the old train line between Kemi and Haparanda.

https://yle.fi/a/74-20220038

(You could also walk the 4.5 km between the currently operated railway stations across the border.)