Cultivate For 72 Hours is a Manga/Manhwa/Manhua in english language, manhua series, english chapters have been translated and you can read them here. You are reading chapters on www.mgeko.cc fastest updating comic site. The Summary is

When Feng Feifan woke up, he found that the Earth had been destroyed. Then, he went back three days in time, and the question arose: would the Earth be destroyed three days later? Furthermore, how was Feng Feifan able to survive? Many unknown mysteries unfolded one by one.