What made the thirty years' war the most destructive military conflict in europe until the 20th century?

the thirty years' war was considered as the most destructive military conflict in europe until the 20th century because eight million lives lost during this war. over the time it became the conflict between great powers of the world and involved large mercenary armies. It is the continuation of the France–Habsburg rivalry.

X= 1.26415 the answer is above

Idon’t know this answer but you can ask google i bet the answer is on there