The thing that stuck with me about exploring in Guild Wars 1 was that there were a number of curious objects with no name, just decorating the countryside. One of the more well-known examples is the Talmark Pillars. I personally remember some sort of glowing, rune-encrusted stone monument just sitting in the middle of nowhere, but I can't for the life of me find it in-game right now.
Were these merely flights of fancy, or was there ever some sort of meaning to them? Honestly I had always expected more of them to show up in GW2. To be fair, the Big One, old Wizard's Folly Tower itself, did make it in.