It is approaching nine o'clock in the evening, and a hush falls when several thousand pairs of eyes are riveted on the huge outdoor stage as the maestro raises his baton before a vast orchestra. You can hear a pin drop. Candles flicker. Hearts are beating.For about six weeks, at the approach of the summer solstice, you can completely forget the world around you and spend blissful nights in the most stunning of venues. We've picked three of the best al fresco venues offering the finest music and settings; two in Italy, one in France.