  We discuss the semiclassical instability of the Randall-Sundrum brane-world
model against a creation of a kind of Kaluza-Klein bubble. An example
describing such a bubble space-time is constructed from the five-dimensional
AdS-Schwarzschild metric. The induced geometry of the brane looks like the
Einstein-Rosen bridge, which connects the positive and the negative tension
branes. The bubble rapidly expands and there also form a trapped region around
it.
