Back to Sid's filmography: Mike Boon (1940-2014) was a truly legendary caver whose many outstanding achievements included being a pioneer in the use of aqualungs for cave diving which allowed him to pass Sumps 6 and 7 in Swildon's Hole; explorations at the far end of Mossdale Caverns with Pete Livesy; exploring major river caves in Mexico, Guatemala, and Jamaica; and a solo exploration to the far end of Castleguard Cave in Canada which he pushed to a glacial ice plug. Following his death in December 2014 Sid Perou put together this tribute to Mike which was first shown at Hidden Earth in September 2015. It was filmed by a number of people in the UK, the USA, and Canada, and put together by Sid. Contributors providing their memories of Mike include Dave Brook, Daryl Donovan, John Donovan, Ian Drummond, Derek Ford, Sid Perou, Peter Thompson, Randy Spahl, Nicholas Vieira, and Carol Whalley, with archive contributions from Ken Pearce and Raymond Stoyles. Derek Ford provides a graphic description of Mike's explorations in Castleguard.