When you travel through Andalusia, you inevitably drive through olive groves. Actually, you do it all the time. The area around Jaen is called 'El mar de olivos' not without reason. But it's hard to say which of these countless olive trees would be included in a nomination and why. The monotonous olive landscape in Andalusia is more reminiscent of the mass product that fills the shelves of our supermarkets than of a cultural heritage of outstanding value. But the same could be said about vineyards, of course.
The T-list entry from 2017 includes a list of 15 areas, but without detailed information and without coordinates. Recently (April 2021) the nomination has been specified. A submission is planned to the WHC in 2023. The proposal was reduced to ten main locations and several sublocations, and Jasam was able to find an official document with maps and coordinates (see this Forum post).

I was happy to see that I had visited one part of the nomination on my Andalusia trip in 2016, the Hacienda La Laguna. At that time there were only news on the web about a planned candidature, but no T-list entry and no details. I had chosen the Hacienda for a visit because it is only ten kilometres from Baeza and because it houses the Museo de la Cultura de Olive. The draft nomination document reads that Hacienda La Laguna represents the period of industrialisation in the first half of the 19th century, when production facilities were modernised and olive growing became more commercial. However, oil is no longer produced at this Hacienda, the modern facilities are in the village of Puente del Obispo, right at the turnoff to the olive grove. The historic estate is quite large and impressive, but unfortunately the main buildings are not accessible. Today they house a hotel and a hotel management school.
The museum is located in an outbuilding and is well worth seeing. All the steps of olive oil production are explained and various historical oil presses are shown. In the garden you can see olive trees from all over the Mediterranean, amazing that there are 30 different varieties. The bodega, the historic storage cellar, can also be visited. It contains ten large oil tanks, each with a capacity of 100,000 litres, in a construction that is called the "Cathedral of Oil" (photos) - a little exaggerated if you ask me.  
After visiting the museum, I took a walk through the olive grove to the lagoon that gave the property its name. It was a beautiful walk of about two kilometres through rather old-looking olive trees. The pond used to be part of the irrigation system, but today the wetland is a nature reserve.

I enjoyed my visit, but all in all, the Hacienda La Laguna had too little to offer for a WHS. Hence my 'thumbs down' rating. But it is certainly unfair or even inappropriate to rate a serial site when you have only visited one part of it. And I don't think that Hacienda La Laguna is a highlight of this serial nomination. The historic haciendas in Cadiz and Seville seem more interesting, espacially if these sites are open to visitors. There is definitely more about this proposal than just the 'Sea of Olives'. Thus, I would probably reconsider my assessment once I had visited more parts of the nomination.
Undoubtedly, olive cultivation and oil production had a significant influence on Mediterranean culture, for thousands of years. Vineyards are World Heritage Sites, many of them, so why not olive groves?