  We propose direct tests of very high energy first-order phase transitions,
which are elusive to collider physics, deploying the gravitational waves
measurements. We show that first-order phase transitions lying into a large
window of critical temperatures, which is considerably larger than the
electroweak energy scale, can be tested from aLIGO and Einstein Telescope. This
provides the possibility to probe several inflationary mechanisms ending with
the inflaton in a false minimum, and high-energy first order phase transitions
that are due to new scalar bosons, beyond the Standard Model of particle
physics. As an important example, we consider the axion monodromy inflationary
scenario, and analyze the potential for its experimental verification,
deploying the gravitational wave interferometers.
