During the life of Jesus, the Roman Empire was the powerhouse of the world. Their military had conquered all of the area surrounding the Mediterranean Sea, as well as the entire Italian peninsula. Rome struck fear into the hearts of its people by the brutal way they treated criminals or people that opposed the empire's ambitions. The most prominent punishment was crucifixion. People condemned to death would be hung on a cross and would basically suffocate to death as their agonizing screams would echo throughout the city.
When Jesus was on the Earth, a cross was a symbol of death! However, after He used it to pay the debt for the sins of the world, it became a symbol of life! Just as Christ brings us from death in our sin to eternal life in Himself, He transformed the cross from a sign of death into one of life! If God could change the purpose of an execution tool into a bridge to Himself, then imagine the things He can transform in your life!