I know about how they just 'revere' the saints and 'ask' them to 'pass a message', but either way I look at it I just can't justify it.
But because they've been around the longest despite the atrocious things they've done in the past, I have to call them "Christian".
But moving on. The Wailing Wall probably isn't idol worship. It's a religious site, sure, but I don't see it being an idol unless they're worshiping the wall itself.