Mérida was, in Roman times, the capital of the large province of Lusitania, which stretched across parts of southern Spain and most of Portugal. It was one of the most important Roman cities on the Iberian peninsula and today is one of 2 Roman-themed WH sites in Spain. The other is Tarragona on the Catalonian coast, also a former provincial capital. Mérida does have a star attraction - the very well-preserved Roman Theatre and Amphitheatre -, something that Tarragona doesn't really provide, but Tarragona probably has a higher number of different Roman sites and buildings than Mérida has, so if you are interested in ancient history, it may be worth checking out both places. There are a handful of reasonably impressive Roman-era buildings sprinkled throughout Mérida, such as the Arch of Trajan, the Temple of Diana, and the Roman Bridge (which can still be used today, similar to the one in Salamanca), and there are some nicely preserved remnants of aqueducts which housed many storks' nests when I visited in October. And right next to the Amphitheatre, there is an excellent Roman Museum with a fantastic collection of mosaics. So even if Mérida is certainly a bit off the beaten track, it is definitely worth a visit for anyone with an interest in Roman history.