360Cities has a large collection of 360 degree panoramic photographs from around the world. There is a little bit of everything: day shots, night shots, exteriors, interiors. Here is one view of the Duomo in Florence as an example. The site features a search in the upper right hand corner of the page that allows you to search by keyword (e.g. city, landmark, event).
Check it out here: http://360cities.net/