If you have ever spent Shabbat in Jerusalem, you will have heard the siren sound 40 minutes before sunset announcing the imminent onset of Shabbat. The city streets begin to fall quiet. This continues a very old tradition dating back to the Temple. The Talmud, (Shabbat 35b) records that six trumpet blasts were sounded on the eve of Shabbat, the first to tell people to cease work in the fields, the second to have shopkeepers close their stores...the third for candle-lighting."
When the Second Temple existed, the trumpeter stood on a platform in a stone specially sculpted for him at the top of the south-west corner of the outer wall. During the excavations of the southern wall after the Six-Day War, the stone was uncovered. It bears the inscription, "The place of the trumpeter". You can see the stone and a replica of the inscription at the south wall archaeological site and the original in the Israel Museum.