  An accretion flow around a black hole has a saddle type sonic point just
outside the event horizon to guarantee that the flow enters the black hole
supersonically. This feature exclusively present in strong gravity limit makes
its marks in every observation of black hole candidates. Another physical sonic
point is present (as in a Bondi flow) even in weak gravity. Every aspect of
spectral or temporal properties of every black hole can be understood using
this transonic or advective flow having more than one saddle type points. This
most well known and generalized solution with viscosity and radiative transfer
has been verified by numerical simulations also. Spectra, computed for various
combinations of the standard Keplerian, and advective sub-Keplerian components
match accurately with those from satellite observations. Standing, oscillating
and propagatory oscillating shocks are produced due to centrifugal barrier of
the advective component. The post-shock region acts as the Compton cloud
producing the power-law spectra. Jets and outflows are also produced from this
post-shock region, commonly known as the CENtrifugal barrier supported BOundary
Layer or CENBOL. In soft states, the CENBOL is cooled down by soft photons from
the Keplerian disk, and thus the outflow is absent. Type-C and Type-B QPOs are
generated respectively due to strong and weak resonance oscillations of the
CENBOL. Away from resonance, oscillation may be triggered when Rankine-Hugoniot
conditions are not satisfied and Type-A QPOs could be seen.
