Under the Roman name Emerita Augusta, Mérida was an important centre on the Via de la Plata (Silver Road), the connection between Seville in Andalusia and Astorga in the north. The ancient city had about 50,000 inhabitants, quite large for the time. Today, Mérida is only slightly larger than it was in Roman times, a cosy and leisurely town compared to other sites in Spain.
I visited Mérida in May 2019 on a trip through central Spain, it was the southernmost of eleven WHS on this tour. The WHS consists of 22 locations, most of which are within walking distance of the city centre, only a few are located in the countryside outside of Mérida. The combined ticket mentioned in Els' review now costs 15 euros, still a reasonable price for five sites. The opening hours are also pleasing: from 9 am to 9 pm without siesta break, quite unusual in Spain.

The Roman Theatre (photo) is certainly the most visited monument in Mérida. It is well preserved, though the capitals of some columns and parts of the upper frieze are missing and the back wall is not complete. But you can still imagine how magnificent the structure might have looked in ancient times. Right next to it is the Amphitheatre, built for gladiator fights and struggles between wild animals. In Roman times it was probably more popular than its neighbour, at least it offered more seats for spectators. However, only the lower tiers have survived, the stones of the upper levels were used for later buildings. The Roman Circus, located outside the ancient city walls, is the third in the series of Roman ‘entertainment buildings’.
The Alcazaba fortress was built by the Umayyads in the 9th century. In the courtyard, remains of Roman structures have been excavated: parts of the main road and the foundations of a city gate. But what I liked best was the view from the fortress walls to the Puente Romano, the Roman bridge. It is an impressive structure with 60 arches and a length of almost 800 meters. Fortunately, it is for pedestrians and cyclists only. Traffic rolls over the modern Lusitania bridge, an early work by one of my favourite contemporary architects, Santiago Calatrava.
The House of Mithraeum, with some mosaics and remains of wall paintings, and the Crypt of Santa Eulalia complete the list of locations included in the combined ticket. Both are of minor interest.
Among the freely accessible sites, two are worth mentioning: the Proserpina Dam and the Milagros Aqueduct. Both were part of the city's water supply. The Proserpina Reservoir is located only five kilometres north of the city and is easily accessible by car. The dam is an earthen dam with retaining wall, with a length of about 400 metres. You can walk along the entire wall, information boards explain the structure of the wall and the hydraulic system of the water supply. The water was brought to Merida via the Milagros Aqueduct. A small part of it has been preserved, namely the arched pillars over the Albarregas River.
Like other reviewers, I would highly recommend a visit to the Roman Museum. Almost all the exhibits are from the archaeological sites of Merida. And it's a great building, the brick architecture and the high arches in the main hall are references to Roman constructions. It is one of the best museum of its kind that I have visited so far.

Merida has no outstanding individual monuments. The quality of the WHS lies in the ensemble of the various components, which provide insights into the structure and everyday life of a Roman city. Comparisons can be made with Tarraco. I rated Merida higher because the ensemble is more complete, the sites are better preserved and because Merida has two highlights with the Roman Theatre and the Roman Museum. Tarraco has nothing comparable to offer.