most (not all, some contributions are QTVR-only due to historical reasons)
Javascript + HTML5 / WebGL
many, but depends on photographer's choice of file upload (newer event = more likely to work) and your device's capabilities. You may experience slow playback, distorted images or unexpected browser quitting if there is only limited memory/GPU power available.
Ancient building underground (middle of XVI century) made to bring water to 'Fontana del Nettuno' fountain in Bologna - Italy.
Project Architect Tommaso Laureti (1530 - 1602) by order of Pio IV Pope.