  Metastable states with T$_{1/2}$ = 8(2) ms in $^{205}$Bi and T$_{1/2}$ =
0.22(2) ms in $^{204}$Pb, with $\approx $ 8 MeV excitation energy and angular
momentum $\ge $ 22 $\hbar $, have been established. These represent, by up to
two orders of magnitude, the longest-lived nuclear states above an excitation
energy of 7 MeV, ever identified in the nuclear chart. Additionally, the
half-life of the 10.17 MeV state in $^{206}$Bi has been determined to be
0.027(2) ms, the next highest value in this highly excited regime. These
observations indicate the emergence of an island of extreme nuclear isomerism
arising from core-excited configurations at high excitation in the vicinity of
the doubly closed-shell nucleus $^{208}$Pb. These results are expected to
provide discriminating tests of the effective interactions used in current
large-scale shell-model calculations.
