world not loading

i was creating a world in minecraft, but it kept stuck on the "downloading terrain" part, i tried loading it again several times after, i also tried creating new worlds but the bug kept appearing.

i do not know exactly if other people are experiencing the same, but i do not know what to do about this (i also tried re-downloading the game several times.)
i can hear the background music of the game, but not see the game itself, so it did not freeze either.
(b.t.w, this website did not allow me to select the newest version 1.8, so i just had to select the older 1.6)