New World

In one fateful day , across the 7 continents which holds 7 of the biggest human cities , 7 powerful magic users cast a world altering spell that turns every human-made structure into overgrown trees by sacrificing their lives and the lives of all the people in the city.
Due to that much life energy the surge of the overgrowth stretched across the other continents creating an intercontinental bridge made up of colossal trees .After the incident , magic and non-human slowly returned in a period of a hundred years . During that time , humans are the only creature with the little affinity to magic and every time they make an advancement in their science and tech , the initial world altering spell cast by the 7 magic users will be triggered and turn it into overgrown tree along with others in a 100 m radius. Taking the lives of all living within that vicinity .So a law is passed that no advancement of the old world shall be rebuilt again. The Council of the 7 dictates that .

first try please be candid