Creating large random landsapes with Hills?

[b0LbiT]

Hi community,

i have finished my first steps in 3D programming and want now to create a large random landscape.

This landscape should be changeable.
For Example, when there is an explosion, this should lower the land at this point.

It schould be a landscape with hills.
But i have no idea, how to do this.
Do you know any links?
Do you have any suggestions?

Thanks fpr tips and help