  The algebraic framework of the interacting boson model with configuration
mixing is employed to demonstrate the occurrence of intertwined quantum phase
transitions (IQPTs) in the $_{40}$Zr isotopes with neutron number 52-70. The
detailed quantum and classical analyses reveal a QPT of crossing normal and
intruder configurations superimposed on a QPT of the intruder configuration
from U(5) to SU(3) and a crossover from SU(3) to SO(6) dynamical symmetries.
