European settlement in Australia in 1988. The pylon was closed from April to November 2000 for the Roads & Traffic Authority and BridgeClimb to create a new exhibition called "Proud Arch". The exhibition focussed on Bradfield, and included a glass direction finder on the observation level, and various important heritage items. The pylon again closed for four weeks in 2003 for the installation of an exhibit called "Dangerous Works", highlighting the dangerous conditions experienced by the original construction workers on the bridge, and two stained glass feature windows in memory of the workers. BridgeClimb In the 1950s and 1960s, there were occasional newspaper reports of climbers who had made illegal arch traversals of the bridge by night. In 1973 Philippe Petit walked across a wire between the two pylons at the southern end of the Sydney Harbour Bridge. Since 1998, BridgeClimb has made it possible for tourists to legally climb the southern half of the bridge. Tours run throughout the day, from dawn to night, and are only cancelled for electrical storms or high wind. Groups of climbers are provided with protective clothing appropriate to the prevailing weather conditions, and are given an orientation briefing before climbing. During the climb, attendees are secured to the bridge by a wire lifeline. Each climb begins on the eastern side of the bridge and ascends to the top. At the summit, the group crosses to the western side of the arch for the descent. Each climb takes three-and-a-half-hours, including the preparations. In December 2006, BridgeClimb launched an alternative to climbing the upper arches of the bridge. The Discovery Climb allows climbers to ascend the lower chord of the bridge and view its internal structure. From the apex of the lower chord, climbers ascend a staircase to a platform at the summit. Celebrations and protests Since the opening, the bridge has been the focal point of much tourism, national pride and even protests 50th Anniversary celebrations In 1982, the 50th anniversary of the opening of the bridge was celebrated. For the first time since its opening in 1932, the bridge was closed to most vehicles with the exception of vintage vehicles, and pedestrians were allowed full access for the day. The celebrations were attended by Edward Judge, who represented Dorman Long. Bicentennial Australia Day celebrations Australia's bicentennial celebrations on 26 January 1988 attracted large crowds in the bridge's vicinity as merrymakers flocked to the