  We comprehensively study the variability of Miras in the Large Magellanic
Cloud (LMC) by simultaneous analysing light curves in 14 bands in the range of
0.5$-$24 microns. We model over 20-years-long, high cadence $I$-band light
curves collected by The Optical Gravitational Lensing Experiment (OGLE) and fit
them to light curves collected in the remaining
optical/near-infrared/mid-infrared bands to derive both the variability
amplitude ratio and phase-lag as a function of wavelength. We show that the
variability amplitude ratio declines with the increasing wavelength for both
oxygen-rich (O-rich) and carbon-rich (C-rich) Miras, while the variability
phase-lag increases slightly with the increasing wavelength. In a significant
number of Miras, mostly the C-rich ones, the spectral energy distributions
(SEDs) require a presence of a cool component (dust) in order to match the
mid-IR data. Based on SED fits for a golden sample of 140 Miras, we calculated
synthetic period-luminosity relations (PLRs) in 42 bands for the existing and
future sky surveys that include OGLE, The VISTA Near-Infrared $YJK_\mathrm{s}$
Survey of the Magellanic Clouds System (VMC), Legacy Survey of Space and Time
(LSST), Gaia, Spitzer, The Wide-field Infrared Survey Explorer (WISE), The
James Webb Space Telescope (JWST), The Nancy Grace Roman Space Telescope
(formerly WFIRST), and The Hubble Space Telescope (HST). We show that the
synthetic PLR slope decreases with increasing wavelength for both the O-rich
and C-rich Miras in the range of 0.1$-$40 microns. Finally, we show the
location and motions of Miras on the color-magnitude (CMD) and color-color
(CCD) diagrams.
