First off, thank you Kyo for recommending this. It was a real entertainer. The manga comes from a guy called UMEZU Kazuo touted as the best horror mangaka of all times. The series starts off brilliantly with an entire school getting yanked off into an alternate dimension where the earth is barren. I know it sounds like an average sci-fi flick and stuff but get this, the manga started in 1972 and going by that if you look at the story and how the starting chapters/volumes go about, you won't even believe it was created so early. Everything is neatly placed and chronicles the adventures of a bunch of students who try and brave the odds of a weird world where they have to fend for themselves from nasty stuff/creatures and most importantly internal power struggle. I loved reading every bit of it and I don't mind giving it another go in a few months.
No of Volumes : 11
Completely Scanlated =D