[sbzodnsbd]

First they were made mostly to defend against the Yugoslavians and the Greeks.

Also, the vast majority of them are the size of a small igloo barely big enough for two, with foot thick reinforced concrete - and they’re everywhere in an onion like structure.

The idea then is that the infantry man retreats to the next layer (some 100 yards or less).

Sure an aircraft an destroy anyone of them. But there are more bunkers than any Air Force can blow up.

Meanwhile the invader has hundreds of kilometers of layers of bunkers to walk through.

Most of the igloos are for rifle men. Every third igloo is open in the back - that’s the RPG guy for the tanks.

Those big bunkers in the photos are quite rare.

Finally, the “commissioning” of the igloo bunker was done by having their designer sit in one of them while the artillary hit it - they’re tough little things.