  The most abundant form of water in the universe probably is its supercooled
state, staying non-crystalline down to lowest temperatures. The many
peculiarities of liquid water, like its partly negative thermal expansion, have
been traced back to prominent anomalies occurring in its supercooled form -
especially under elevated pressure - and to the presence of two variants of
supercooled water and of amorphous, glassy ice. However, the bare existence of
these different liquid states and of a related liquid-liquid crossover at
ambient pressure are controversially debated since decades, just as the
absolute value of water's glass-transition temperature. Their direct
experimental detection is hampered by the inevitable crystallization of pure
water in a certain temperature range, termed "no-man's land". To tackle these
problems, we have applied dielectric spectroscopy and differential scanning
calorimetry to aqueous LiCl solutions. By covering a frequency range of up to
14 decades and by quenching some of the solutions to avoid crystallization,
here we show that there are indeed strong hints at two forms of water,
occurring in different temperature ranges and having different glass-transition
temperatures, even at ambient pressure: A so-called "fragile" liquid,
characterized by super-Arrhenius temperature dependence of the molecular
dynamics at high temperatures, and a "strong" liquid, nearly following
Arrhenius behaviour, at low temperatures.
