Where?

The war happened in Verdun France.

What led to its occurrence?

The Germans wanted to take/capture Paris, but the French would not let it happen, though.

Battle conditions?

The grounds were muddy, and had pole laid out with barbed wire, and the men had to handle the trenches being flooded in bad rainy days, and it was contaminated with rats and insects.

Terrain?

They fought on fields, in horrible trenches that were over 10ft tall