Video and photos of an unusual glowing multi-colored ”mushroom cloud” hanging over Beijing skyline scared internet users who couldn’t make out what it was. An unusual sight lit up Beijing skyline – a huge glowing mushroom cloud hung over the city around 7 pm local time. It covered several miles and stayed in the air for about an hour, gradually taking the shape of an atomic bomb explosion. It then gave way to more surprises – a further spectacle of lightning strikes lit up the evening skies, making the site even more ominous. But instead of being a danger to residents or marking imminent the Apocalypse, predicted by the Mayan calendar, the phenomenon was reported to be completely harmless.It is thought to have been a giant cumulonimbus cloud – a vertical tower which is typically associated with thunderstorms.Chinese authorities however advised residents of Beijing to stay inside on Monday on account of the green, yellow and orange "mushroom cloud," according to Agence France-Presse. Many have expressed shock that a formation so similar to that of the after effects of an atomic bomb could appear over their city.