Topographic Google Map?

I'm looking for a simple, online topographic map that highlights various elevation ranges in different countries as I travel around the world. I like how Google Maps is set-up (with zoom, and text) so something like that would probably work best. My purpose in using the map is to better plan my routes, and destinations. I'd like to know where the mountains are, and how tall they are in each respective country by looking at a map. I'd also like to know where the towns are in proximity to the mountains (i.e are they in the mountains, in between mountains, etc...).

Thx.