10 milliwatts from Croatia and decoded at K3FEF SDR in Milford PA, WSPR isn't good at conveying large amounts of information (it takes four minutes per cycle just to get basic info), but holy moly, 10 milliwatts covering 6954 km! It's always possible that the power isn't being self-reported properly (most are 200mw-5w, but I think the transmitter reports its own power so should be reliable) but if it is accurate that's pretty remarkable.