In vanilla Civ V the fort tile improvement and the citadel both change how they look when you reach the Industrial Age. They become modernized bases with radio towers and 20th-century artillery. The problem here id that the Industrial Era represents the 19th century, and it just doesn't feel right for me to have my Civil War-era soldiers stationed in a World Wars-era fort. So say I just wanted to change the time when the fort and citadel change from the Industrial Age to the Modern Age. How would I go about doing that? Would I need to go into the .fpk files?