Frederic and Joel covered the site pretty well, so I will try to add a few information from my side as the first reviewer after that visited the site after the inscription.

Important to mention is, that the Escuela Superior de Mecánica de la Armada (ESMA) is a pretty big and interesting campus, that includes five accessible buildings, many none accessible buildings that are still used today, old watch towers and also one of the planes that were used to drop dissident into Rio Plata. But only the Officers Quarters Building at the very corner of the campus is core zone. The rest is buffer zone. I highly recommend to visit the buffer zone as well, as it is very interesting and shows additional testimony of the victims. Our Uber dropped us off in front of the building, but unfortunately the entrance to the campus is almost at the other corner of Av. Del Libertador, which was a 400 meters walk not appreciated by my family.

Entry is free, but children (below 16) are not allowed to enter the inscribed building. Out of the four levels, only two could actually be visited. The officers quarters on level 2 and 3 were closed and I am not sure if it is planned to make them accessible (again). The relatively small number of accessible rooms makes this a relatively short visit. You can however spend lots of time in there watching all the testimony videos that are shown in the different rooms and read the info boards. It is also very unphotogenic on the inside. Basically small empty rooms with mostly info boards and video installations. There is nothing special about the building itself. This led to me not taking the usually way too many pictures of a WHS, despite the nice weather.

I totally agree with the other reviewers about the UOV. This is AOV (Argentinian Outstanding Value). It’s tragic, but I don’t see the worldwide impact. However, if you visit Argentina, chances are high you enter via Buenos Aires and this is a very easy tick as well as an good place to pick up some local history.