Construction of defence line Salpa (Salpa-asema) began later 1940. Volunteers worked there in the beginning, then peoples ineligible for war service were mobilized. Maximum number of workers, near to 35000, worked there spring 1941. After beginning of Continuation War in 1941 fortification works were stopped, pillboxes and bunkers were disarmed and all armaments were sent at the front. In the beginning of 1944 works on the Line were resumed and proceed till the end of Continuation War September, 4, 1944.
728 various concrete installations, 315 km wire obstacles, 225 km anti-tank obstacles, 130 km anti-tank ditches, more than 3000 entrenchments, 254 concrete infantry shelters, endless trench, rifleman's cells, dig-outs and etc. composed the power of this defence line. 90% all concrete installations are in the line sector between Finnish Gulf and Saima lake system.
Salpa Line has much more depth than Mannerheim Line. Gap between front installations (Virolahti, Miehikkälä, Ylämaa, Lappeenranta) and rear ones (Hamina, Luumäki, Lemi) reaches few tens kilometers.
Basic concrete installations are machine gun's or artillery-machine-gun's caponier of flank fire with shelter for 20 men, command point with shelter for 40 men and spherical shelter for 10-15 men. Installations has a floors of 2 m thick and frontal walls 2.3 m thick and can endure single 420 mm artillery shell hit or 1000 kg bomb hit.
Salpa Line is the greater fortification project in Scandinavia and one of the largest in the world. It has never taken part in action but Finns believe that huge efforts of it's construction were quite necessary. Existence of Salpa Line was a matter during the Soviet-Finnish peace negotiations autumn 1944.
War monuments and museums has been made in many pillboxes along highways and main roads. There are the electricity light in that pillboxes and bunkers, armaments, the trenches, entrenchments and fragments of wire obstacles are restored thoroughly. The museums of Salpa Line are opened 10-18 'clock summer-time. Single bunkers which are not included in museums can be locked, but you always can order the tour by phone or e-mail.
This is very impressive and strong fortified line (region - to be more exact). It is ever so much stronger than Finnish Mannerheim Line and equal to Soviet KaUR (Karelian Fortified Region) on the Karelian Isthmus.
I was impressed by respect of Finns to their history and history of Winter War especially, despite of their defeat in that war.
There are the numerous pointers and notice-boards with information, drawings and detail maps of fortified installations along side of the roads. There are phone numbers and e-mails on that boards for ordering of guided bunker's tours. Pillboxes are clean and painted. There are wooden benches and tables for the rest of tired bunker's explorers. There are the toilets. There are ash-bins, electricity in pillboxes and bier's stalls... Why I say all about it? You've never seen the KaUR bunkers in Russia...