a reply to: RAY1990
this ww1 battle would disagree with you when people did just that and ended a three year stale mate in trench warfare
if it was not such an effective tactic on the rare chance an enemy can attack static defenses why are some of the times they were used listed as some
of the largest non nuclear explosions in history ,its the old problem of having fixed defenses(Israeli side) that the enemy can tunnel under and
undermine and pop up and cause some chaos or blow up something reasonably well.imagine had they stopped firing rockets for 3 months and instead used
all the explosives under either the wall or other important areas and set it all off at once it would be a highly effective symbol and a victory they
could hang their hats on so to speak by getting to the Israeli heart land while avoiding their feared air force
Battle of Messines On 7 June 1917, nineteen (of a planned twenty-one) large mines, containing a total of over 455 tons of ammonal
explosives, were set off beneath German lines on the Messines-Wytschaete ridge. The explosion, which killed about 10,000 Germans, was heard as far
away as London and Dublin. While determining the power of explosions is difficult, this was probably the largest planned explosion in history until
the 1945 Trinity atomic weapon test, and the largest non-nuclear planned explosion until the 1947 British Heligoland detonation (below). The Messines
mines detonation killed more people than any other non-nuclear man-made explosion in history.
Old perhaps ineffective not at all ,10,000
entrenched and highly fortified German troops literally thrown into the sky by the force of the blast,they had been holding that hill for three years
in fortifications that appeared impenetrable but the moles got them .
on your 40 times challenge the entirety of ww1 was basically forms of tunneling(trench warfare) undermining might be a bit different but tunneling is
quite common even in the modern age,look at north korea they got all kinds of stuff hollowed out to try to increase survivability of their arty ,the
entirety of Switzerland is a honeycomb of fortresses and rigged explosives to bring mountains down on their enemies and close off paths.Vietnam go ask
their irregulars or ask a tunnel rat (if any of them are still alive and sane after what they lived through) about tunnel warfare and was used in a
good deal of civil war battles in usa as well.
cannons did not stop this mining(blowing them up from below)
much more famous case of mining an enemy strong hold held with artillery and cannons and other modern
Another example is recorded in Luis Trenker's Mountains on Fire (1931). Whole mountain peaks in the Alps, such as Col di Lana, Lagazuoi and
Marmolata, were detonated during the Italian Campaign of World War I.
so two from ww1 again
more then a few from nam area and we were hitting them with bombers and legit carpet bombings
and even a few battles from the Syrian civil war used these tactics
used in the ruso Japanese war as well (siege of port Arthur)
used sparingly here but hey it counts
too many times to count in korea (them north Koreans are efficent moles) often building entire fortified garrisons under ground same for the Chinese
Japanese war that was the prelude to ww2(the Japanese flooded the tunnels with toxic gas and water) so that surely gets tunnels in modern times up to
tunnels were used in the sino Vietnamese war as well
bin-laden hid in tora bora for a while probably the most well know recent tunnel/cave system
dont underestimate sappers/combat engineers they have achieved amazing victories in the past and just because a tactic is old does not make it useless
otherwise people would not still study Hannibal's complete double envelopment of the Romans at cannane.
TLDR tunnels they are effective and it is never wise to let troops have free access to your flanks or other suposedly safe areas