Because of the concern for the potential damage caused by travel to the Liberty Bell, the city officials in Philadelphia initially denied San Francisco's request to exhibit the Bell. However, city officials changed their minds when they received a petition signed by over 200,000 California schoolchildren requesting the Liberty Bell. To ensure its safety throughout a long trip across the country, engineers fitted the Liberty Bell with a special brace called a spider. This iron device fit inside the Bell and supported its weight and clapper with six curved arms clamped to the Bell's rim. The Liberty Bell still wears the spider today.