According to Einstein, you need to describe where you are not only in three-dimensional space* — length, width and height — but also in time. Time is the fourth dimension. So to know where you are, you have to know what time it is. Your complete answer should be "I'm sitting on a 4-foot-high aardvark at the northeast corner of Bern St. and Ulm St., and it's July 1st, 2002, at 1:23 p.m. on my watch." Einstein called a description that used four dimensions an event. *By "space," we mean the space that is all around us, not just outer space.