I make my Life in Madrid, so I know this world heritage site very well. I followed Its inscription closely and I was convinced It was going to be deferred. For better or worse It got accepted.

The sites essentially consista of two components: the retiro and the paseo del Prado, with the barrio de los jeronimos acting as a Bridge between the two.

Let's start with the Paseo del Prado. In It's review Icomos isn't as harsh as one might think. The prado avenue IS widely regarded as the first "alameda", a tree lined avenue of public use typical in hispanic cities. The integrity is questionable (alameda means poplar forest and there are no poplars left) but the general idea is still there and Icomos brought the concept as I personally do too.

Furthermore, as the name implies, this area was chosen by Charles III to build a space for arts and sciences. As a quick note, this project played an important role in the introduction of neoclasicism in Spain. Some of the institutions founded still mantain their scientific or artistic use. Probably the most true to It's original value is the botanical garden, which tbh IS small and not overly impressive, but It's quite historically relevant, given its many conections with latin America. It's at It's core what the site would like to be...and isn't. most sites here are relics of the past. They changed functions long ago, though their unimpressive and common neoclasical architecture can still be seen. The prado museum was to be of natural sciences in origin and the observatory is no longer in use. As such the connection and especially the relevance of this project IS subject to interpretation. Clearly a European project focused on building artistic and scientific institutions isn't unique and imho It's better represented in the museeninsel in Berlin.

Then there's the retiro which Icomos considered little more than a glorified urban park. Madrid has certainly gone to great extenses to include it in the proposal. 

Apart from any OUV this site might have, It's undeniable It's worth a visit. This property houses one of the most impressive art collections in the world. The prado, the reina Sofía and the Thyssen are all world class museums. The paseo del Prado is peppered with interesting buildings, like the eclectic city hall and the atocha station.