Rob, there is no need to go anywhere else for tourist info.
the main multimadrid site at
www.multimadrid.com/hogar.htm has tons of info (although i have neglected the retiro, very little time to add it lately) on sights of madrid. there are photos, videos and descriptions.
i know that the forums are the most interactive part of this site but there is A LOT MORE that was here years before i added the forums.
you can see it all at
www.multimadrid.com/hogar.htm .
there are some 360º panoramic views (currently re-doing them bit by bit in spherical panoramas) of the retiro at
http://www.multimadrid.com/panoramics/index.htm , including 2 views of the palacio de cristal at the retiro

it was next to impossible due to the poorly designed navigation of the esmadrid site but after a loooong while, i found the following description of the palacio de cristal...
quote:
Similarly to the Palacio de Velázquez, the Palacio de Cristal in the Retiro Park was built for the imminent holding of an Exhibition, in this case that of the Philippines, in 1887. The architect was also the same for both buildings, Ricardo Velázquez Bosco, who complied with the order to build the Palacio de Cristal in five months. He designed a magnificent greenhouse in which to exhibit exotic plants and flowers from the Philippines, and it is considered one of the best examples of iron and glass architecture in the country. With this building, Madrid joined the list of other European capitals that were starting to use this type of construction.
This beautiful building is 54 meters long, 28 metres wide and 22.6 metres high at its highest point and was built on a brick base decorated with a fine line of ceramics. The layout is similar to that of the transept and presbytery of a church whilst the iron structure is covered with panes of glass, some of which open as ventilation windows. Access to the palace is by way of an Ionic-columned portico and it faces a lake surrounded by trees.
all in all, the esmadrid site is pretty weak, they should be ashamed as the site is the official website for madrid tourism and with their budget, they should be able to do a LOT better.
saludos,
jer...