Most gladiators were usually slaves. Slavers sell slaves for money and the slaves are forced into an arena to fight to their deaths.Typically, a slave gladiator goes against a super strong and powerful guy that was not a slave. The spectators would typically want the super strong and powerful guy to win.
The more people that are migrating to urban areas (urbanization) needs more crops for the citizens which causes more people to grow crops and without crop rotating or methods to prevent soil degradation. More likely answer is that more industry grows in the urbanized areas and they have poor management of the soil which causes soil degradation<span />
There's a calculator in this planet earth just use that. It's easy
Channel Tunnel, CN Tower, Empire State Building, Golden Gate Bridge, Itaipu Dam, North Sea Protection Works (Netherlands), Panama Canal. Hope this helps!
