The claim that Quantum Gravity effects destroy the classical black hole
horizon and replace it by horizon-size structure (fuzzball/firewall) is
rather bold but is supported in String Theory. I will discuss signs of this
breakdown of effective field theory at the horizon for supersymmetric and
Schwarzschild black holes and investigate their implications. An important
question about black hole microstate dynamics is to understand how a
collapsing star evolves into horizon-size structure rather than forming a
horizon. To address this question I will study quantum tunneling into black
hole microstate geometries and discuss features of their typical tunneling
end states.