This is Břevnovsky Klaster (Břevnov Monastery) in Prague. You can read all about it on Wikipedia.
Shot with a Canon 550D and Sigma 8mm fisheye lens using only four photos. It was stitched using Panomonkey without any further retouching.
To shoot a fully spherical panorama like this one using only four photos, it’s best to have an SLR camera (I prefer Canon) and an 8mm fisheye lens. You can read more about it on our “how to shoot panoramas” page.