This picture from Pylos is one of my favorites, not so much because it's a beautiful shot as that it's funny. You can hardly see it here but the little sign tells us that this pile of dirt is a Βωμος, i.e. an altar - I do hope that the excavation report is very detailed on the matter, as it's highly probable that all the hard evidence was destroyed when they excavated the place.
The beauty of this is that, as a visitor at almost any archaeological site, you'll find yourself facing this kind of sign over and over again. They may be more or less reasonable, but the bitter truth is that you can't do anything in the end but to trust that the excavator did a good job or use your common sense (and previous experiences) to decide what you find plausible.