  We present a high-resolution smoothed particle hydrodynamics simulation of
the Antennae galaxies (NGC 4038/4039) and follow the evolution $3$ Gyrs beyond
the final coalescence. The simulation includes metallicity dependent cooling,
star formation, and both stellar feedback and chemical enrichment. The
simulated best-match Antennae reproduces well both the observed morphology and
the off-nuclear starburst. We also produce for the first time a simulated
two-dimensional metallicity map of the Antennae and find good agreement with
the observed metallicity of off-nuclear stellar clusters, however the nuclear
metallicities are overproduced by $\sim 0.5$ dex. Using the radiative transfer
code SKIRT we produce multi-wavelength observations of both the Antennae and
the merger remnant. The $1$ Gyr old remnant is well fitted with a S\'ersic
profile of $n=7.07$, and with an $r$-band effective radius of $r_{\mathrm{e}}=
1.6$ kpc and velocity dispersion of $\sigma_{\mathrm{e}}=180$ km$/$s the
remnant is located on the fundamental plane of early-type galaxies (ETGs). The
initially blue Antennae remnant evolves onto the red sequence after $\sim 2.5$
Gyr of secular evolution. The remnant would be classified as a fast rotator, as
the specific angular momentum evolves from $\lambda_{\mathrm{Re}}\approx0.11$
to $\lambda_{\mathrm{Re}}\approx0.14$ during its evolution. The remnant shows
ordered rotation and a double peaked maximum in the mean 2D line-of-sight
velocity. These kinematical features are relatively common among local ETGs and
we specifically identify three local ETGs (NGC 3226, NGC 3379 and NGC 4494) in
the ATLAS$^\mathrm{3D}$ sample, whose photometric and kinematic properties most
resemble the Antennae remnant.
