The Telegraph reports:

Deep in the Estonian forest, a concrete bunker designed to withstand a direct hit by Russian artillery is being installed.

It is the first of a network of 600 fortified structures to be built in peacetime as a “tripwire” defence strategy to protect the most exposed part of Nato’s eastern flank from a possible invasion.

Europe is rebuilding the Maginot line that famously failed to deter the Germans in WW2, the remains of which should have reminded NATO of the folly of relying on lines of bunkers to deter invaders. 

During the Cold War the 'tripwire' for a massed Soviet tank invasion was the British Army of the Rhine (BAOR), which was famously expected to last a few days before being destroyed.

[https://nationalinterest.org/blog/buzz/british-tank-army-expected-last-just-few-days-against-russians-126717] 

The strange thing is that the EU will not build walls to stop the inflow of illegal migrants but will spend a fortune to build defensive bunkers that will have little strategic or tactical purpose when everything behind them is reduced to ashes - except as somewhere to hang out waiting for the radiation to reach you.

They would be better off just stuffing the bunkers with a bunch of kamikaze robots to be unleashed in the event that anyone is daft enough to want to invade Estonia through snow-laden forests.

Bonkers!