The human cost of World War I was

The human cost of World War I was enormous. More than 9 million soldiers and an estimated 12 million civilians died in the four-year-long conflict, which also left 21 million military men wounded. "Many of them were missing arms, legs, hands, genitals or driven mad by shell shock," says historian Adam Hochschild

i think they would live in caves or natural tunnels

the triple alliance. germany and austria-hungary were already allies by 1879 when, worried about a threat from russia, they formed the dual alliance. italy joined the group in 1882. there was a concern about a possible attack from france and the alliance needed powerful friends to defend it.