The online virtual tour of the Smithsonian National Museum of Natural History has always been a favorite resource of mine for the classroom. Students can virtually take a field trip and tour the many displays in 360 views of different areas of the museum. There is now a mobile friendly version of this site that has made this site possible on the mobile devices, both iOS and Android.
Choose the gallery that you would like to visit from the list. Each gallery is full of many rooms. Geology, Egyptian mummies, mammals, the Ice Age, fossils.... just to name a few!
Inside each room your can use your finger to move in all directions and zoom in closer on displays. Tap on the images along the bottom to move, or use the arrows on the iPad to move to the next room.
This is a mobile friendly website, not an app. To save it to your iPad for easy access by students, add the address to the Home Screen.