"Sevilla 111 Gigapixels is a huge panoramic and interactive photograph of Seville city, which consists of 111 billions pixels. A new worldwide record since December 2010." http://www.sevilla111.com/default_en.htm Apologies if this is a re-post.
Very cool. There are a few knocking about of various cities. One was taken with a Sony Full Frame DSLR.