I've often thought that a lot of Radio 4's output is essentially obsessive compulsive. You get a lot of slightly unhinged programming. Themes that are just a little bit too narrow, people who are ever-so-slightly too immersed in their subject. Don't get me wrong: this is a good thing.

I think Radio 4 preserves a slightly out-of-date (almost Victorian) curiosity about the world: collecting and cataloguing, preserving and promoting. Radio 4's a bit like a Victorian Museum: an essentially indiscriminate collection of curiosities. The stuffed Ox next to the Persian rug next to the bronze age funerary goods...

If you were up at 5:45 this morning you'd have heard a good example. Part three of Susan Marling's Five Gardens of Germany, in which she walks us around the picturesque grounds of the Rococo palace built by the Bavarian king everyone called Mad Ludwig. The show ends, entirely appropriately, in the world's largest artificial cave to the sound of Wagner (MP3).

The pic of King Ludwig II just after his accession to the throne is from the Wikimedia Commons.