I don't know about the highest, but I was recently charged what I thought the lowest price on a call from an 'unnamed' hotel in Zurich to the US. I made the call about 11:30 pm in Zurich to New Jersey--and while I was not on long--about 2 minutes (I got the answering maching at home), I did leave a message. My charge on the bill was Sfr .50 (about 29 cents US). I don't want to name the hotel, in case they (or their main company) reads these posts & decides to review my bill!