Recent multiwavelength observations of 3C 454.3, in particular during its giant outburst in 2005, put severe constraints on the location of the "blazar zone," its dissipative nature, and high-energy radiation mechanisms. As the optical, X-ray, and millimeter light curves indicate, a significant fraction of the jet energy must be released in the vicinity of the millimeter photosphere; i.e., at distances where, due to lateral expansion, the jet becomes transparent at millimeter wavelengths. We conclude that this region is located at ～10 pc, which is also the distance that coincides with the location of the hot dust region. This location is consistent with the high-amplitude variations observed on a ～10 day timescale, provided that the Lorentz factor of a jet is Γ_j ～ 20. We argue that dissipation is driven by the reconfinement shock and demonstrate that X-rays and γ-rays are likely to be produced via inverse Compton scattering of near- and mid-IR photons emitted by the hot dust. We also infer that the largest gamma-to-synchrotron luminosity ratio ever recorded in this object, which took place during its lowest luminosity states, could be simply due to weaker magnetic fields carried by a less powerful jet.
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