The Roman Forum is preserved as an open archaeological square a short walk from the Templo de Diana. What you see is a partial reconstruction: a portico of Tuscan columns rebuilt from fragments excavated on the site, statues of caryatids modelled on those from the Forum of Augustus in Rome, a stretch of imperial inscriptions along the back wall. It is a clear, fast introduction to what the central square of Augusta Emerita looked like.
The site is free to visit and never busy. Pair it with the nearby Templo de Diana and the Provincial Forum a couple of blocks west — Mérida has two forums, the municipal one here and the larger provincial forum belonging to the wider Roman province of Lusitania.