Do you really need tomatoes to make pizza?

[RadiantDanceMachine]

Teeqoz said:

So I had this discussion with someone about wether or not you need tomatoes to make pizza (yes lol, it's true). Now, I said that you don't, because there is such a thing as "pizza bianca" (ie. "white pizza"), which is  pizza without tomato sauce. Here's a picture:

(mmmmmmm)

My friend however, simply called that "cheese on toast", and claimed that it wasn't pizza. So what do you think, VGC? Can you make pizza without tomato sauce, like in the picture above, or is that just "cheese on toast"? And just for fun, can you also make pizza without cheese?

There is a restaurant called schlotzsky's deli that has pizza with no sauce. It's actually really good in my opinion.