A herd of Texas Longhorns is driven down Exchange Avenue by drovers in period dress twice a day, every day, in what the city bills as the world's only twice-daily cattle drive. It takes about ten minutes and costs nothing to watch. The drive is a staged piece of civic theatre rather than a working operation, and knowing that does not much diminish it — the animals are enormous and the horns genuinely are as wide as the photographs suggest. Stand on the north side of Exchange for the better light, and arrive fifteen minutes early in high season if you want the front rail.