A 14year study of Hong Kong's Earth Hour participation has revealed that it's not the millions of apartment windows or office buildings that steal our night sky, but rather a small handful of brightly lit skyscrapers and LED advertising boards that have an outsized impact on darkness above cities. When these decorative lights and digital screens go dark, the night sky becomes up to 50% darker, offering a hopeful new strategy for tackling light pollution without requiring massive citywide changes. Could this be he the change that dramatically improve night sky visibility for stargazers, wildlife, and anyone hoping to reconnect with the the night sky above our urban landscapes?