  Attosecond angular streaking, also known as the "attoclock", employs a short
elliptically polarized laser pulse to tunnel ionize an electron from an atom or
a molecule and to put a time stamp on this process by deflecting the
photoelectron in the angular spatial direction. This deflection can be used to
evaluate the time the tunneling electron spends under the classically
inaccessible barrier and to determine whether this time is finite. In this
review, we examine the latest experimental and theoretical findings and present
a comprehensive set of evidence supporting the zero tunneling time scenario.
