Before starting, click the left mouse button. You should get a notice that the web site has control of your pointer. Then, use W, A, S, and D keys to move around, and the mouse to look around.
This virtual Etruscan temple is a 3d version of the temple illustrated in fig. 6-3 of Gardner's Art through the Ages: The Western Perspective, 15th ed., vol. 1 (Cengage Learning, 2017).