Former industrial sites can be divisive World Heritage Sites. I'm not against industrial sites (partially as they can be interesting to photograph), although a multitude of mining and planned town sites being inscribed can be monotonous. Fray Bentos though stands out as a unique and key site for international meat exports (stock cubes and canned corned beef). In the modern era, you forget how big a development these were. The products from this factory were one of the most important exports of South America, shipped to Europe and used on expeditions of exploration and to supply armies in both WWI and WWII.

The site itself could do with an up-to-date website. Google Maps indicates it's open Thursday to Sunday, but the sign at the entry states it's open Tuesday to Sunday, only closed on Mondays except holidays, with free entry on Tuesday. We had planned to go on the twice daily tour (10am and 3pm, except on rainy or stormy days), but the lady at the ticket counter suggested we skip as we can't speak Spanish. Two of the participants on the tour later volunteered to translate for us, but we decided to still skip.

The tour is required to enter parts of the former factory, but with our museum ticket we saw both floors of the museum (rather adhoc and mainly in Spanish), plus wandered parts of the site. Our favourite part were the large photos dating back to the 1930s (look for the many workers without shoes!)

We also visited the Casa Grande which is open on selected days, but didn't feel it was that interesting. If you visit on a Monday or outside opening hours, it's still possible to see parts of the factory from the outside, plus the old jetty and wander through the housing area. It's quite a large area that's inscribed, starting from the large sign on the pleasant waterfront walkway. 

If you don't speak Spanish, I recommend stopping at the visitors centre first, before the museum. (We visited afterwards, as it wasn't yet open at 9:45am on a Sunday). There's a few rather high-tech exhibits that give a good introduction in Spanish, English and Portuguese. 

The modern town of Fray Bentos is quite a nice regional town, better than we expected considering its main industry shut down in the 70s. There's multiple buses per day to/from Montevideo, although only one bus per day to and from Colonia - double check the timetables before planning a loop around the WHS in Uruguay. We recommend the pasta restaurant "Wolves" next to the museum with their homemade pasta, although the red wine was far too chilled.