number of operations along with the rest of the 173rd Brigade in areas such as Ben Cat, War Zone D and the Iron Triangle. In January 1966 1 RAR took part in Operation Crimp, a search and destroy mission in the Ho Bo Woods, north of Saigon, during which the battalion conducted an air assault and uncovered the Cu Chi tunnel complex which was serving as the underground hideaway for a VC higher command element. A large stockpile of weapons and a large number of documents were found in the tunnel complex which was the deepest and most elaborate system that had been found up to that time. 1RAR continued operations until April 1966, taking part in a number of joint operations with US troops until the arrival of the 1st Australian Task Force. On Anzac Day, as the battalion was preparing to return to Australia, they were visited by Prime Minister Harold Holt. They were finally relieved in June and they returned to Australia that same month. The battalion's second tour came two years later when it arrived at Nui Dat on 9 April 1968 to relieve 7 RAR. Operating out of Phuoc Tuy Province the battalion was mainly involved in patrols, searches, reconnaissance and security operations before being redeployed in May to an area north of Saigon where throughout April it participated in Operation Toan Thang, which was aimed at cutting off the withdrawal of VC and People's Army of Vietnam (PAVN) forces following the Tet Offensive. After conducting two small operations in Long Khanh Province, 1 RAR moved to Fire Support Base Coral. Whilst they were there, the base was attacked twice. The first attack which on the night of 15 May was only a probing attack by a battalion-sized element, whilst the second attack came on the night of 16 May 1966, when the base was attacked by a force later identified as the PAVN 141st Regiment. After fierce fighting with the help of accurate artillery fire from the 102nd Field Battery the attack was beaten off and on 6 June 1966 the fire base was closed and 1 RAR returned to Nui Dat. Later it was estimated that 162 PAVN were killed as a result of Operation Toan Thang. The Battalion was awarded the Unit Citation for Gallantry in 2018 on the 50th anniversary of the battle. Between July and September several more operations were