LEGO artist Thorsten Bonsch, also known as Xenomurphy, spent a year designing and building his gothic revival take on Gotham City's Arkham Asylum. And he has released a free PDF guide to his building process.
Bonsch took elements from both Batman and H.P. Lovecraft in designing his version of Arkham, and it's filled with wonderful details like Poison Ivy's plants bursting from her room. He has posted his entire 82-page guide to the build (in English and German) to Flickr with photos of the structure from various angles, but he has also made it available as a PDF (just click "Regular Download").