Geologists had long warned that the structure was eroding fast. Rock falls and fissures were reported in subsequent years. Authorities had already banned visitors from walking on top of it. The government last month enacted €1,500 fines ($2,300) for anyone caught walking across the arch. The formation, which was created after two limestone sea caves collapsed, was very popular among scuba divers and one of Malta’s major tourist attractions and it was a popular backdrop in photographs.. The arch was featured in international films. It was a backdrop for the “Game of Thrones” TV series. The window also served as a backdrop in the 1981 movie “Clash of the Titans.” The Environment and Resources Authority called the collapse a major loss to Malta’s natural heritage.