h2g2 The Hitchhiker's Guide to the Galaxy: Earth Edition

I have been to the Sagrada Familia and was entranced and delighted by it, though you soon realise all the postcards and posters have been tinkered with to remove the construction cranes which soar into the sky to enable the building to continue.

If you go don't just stay outside, but go into the crypt. The exhibition there is marvelous and I will always remember Gaudi's string cathedral which he put together. Strings hang down with other strings attached and small weights attached to the very bottom strings so that Gaudi could observe how the curves would appear naturally. He then used this as a guide for making the design of the non-string cathedral. There is a mirror below this upside down string cathedral so that you can see it the right way up.