moving on dynamic pieces based world (like minecraft)

How should I make the navigation on a Minecraft like world?
In minecraft, the ground are just blocks and can change dynamically.
I guess NaviMesh is not suitable here because it require baking.
Should I use pure physics to control the character?

 

Hmmmmmmmmm. Read this, googled it... Thought about it. Thought on it some more...

What I would do.. and this may totally not be an option, just brain storming here...

I would add 100k cubes in the map spaced about .02 apart in all directions then disable them. have Unity 'procedurally' .. randomly turn them back on... Basically a simple algorithm that ensures that nothing floats... however you want to do it.. This way, everything can be navmeshed at the start and all 'top' surfaces of the cubes would be walkable.. Then you could do some magic with textures / onhits / collisions to make it 'break' up.. If feasible, it would take about a day to complete.