I was able to get the last thing of merging Nymph Temples togehter and it's called "The Lost City".

It looks like a big booby statue Castle and if i click on it, it gives Nymph shells. Now i fear, if i click it to often, it dissapiers. Did anyone else got it and can tell me if it dissapiers? I mean im close to sure it will happen, otherwise this would be a game breaking item, but it was alot of work to get it.