Beholder is a web app for building 3D models of objects using photos. You'll need 20 or more high quality photos, taken in a ring around your object of interest, and then Beholder lets you convert this into a textured 3D model that you can download.

Beholder is useful if you want a 3D model of something but you don't have the budget to hire a 3D artist to build it for you. It works on objects of any size, so use a phone or DSLR to take photos of smaller objects or a drone to take photos of buildings.