Photo taken on Aug. 24, 2019 shows a fast-roping display from a helicopter during the open day of the Australian Defence Force Academy (ADFA) in Canberra, Australia. The annual open day of the ADFA was held here on Saturday with a range of displays. (Photo: Chu Chen/Xinhua)

Photo taken on Aug. 24, 2019 shows a simulated ground attack during the open day of the Australian Defence Force Academy (ADFA) in Canberra, Australia. The annual open day of the ADFA was held here on Saturday with a range of displays. (Photo: Chu Chen/Xinhua)

Photo taken on Aug. 24, 2019 shows a rifle spinning demonstration during the open day of the Australian Defence Force Academy (ADFA) in Canberra, Australia. The annual open day of the ADFA was held here on Saturday with a range of displays. (Photo: Chu Chen/Xinhua)

Photo taken on Aug. 24, 2019 shows a parachute display during the open day of the Australian Defence Force Academy (ADFA) in Canberra, Australia. The annual open day of the ADFA was held here on Saturday with a range of displays. (Photo: Chu Chen/Xinhua)

Photo taken on Aug. 24, 2019 shows a simulated ground attack during the open day of the Australian Defence Force Academy (ADFA) in Canberra, Australia. The annual open day of the ADFA was held here on Saturday with a range of displays. (Photo: Chu Chen/Xinhua)

Photo taken on Aug. 24, 2019 shows a band performance during the open day of the Australian Defence Force Academy (ADFA) in Canberra, Australia. The annual open day of the ADFA was held here on Saturday with a range of displays. (Photo: Chu Chen/Xinhua)

Photo taken on Aug. 24, 2019 shows a simulated ground attack during the open day of the Australian Defence Force Academy (ADFA) in Canberra, Australia. The annual open day of the ADFA was held here on Saturday with a range of displays. (Photo: Chu Chen/Xinhua)

Photo taken on Aug. 24, 2019 shows an army dog display during the open day of the Australian Defence Force Academy (ADFA) in Canberra, Australia. The annual open day of the ADFA was held here on Saturday with a range of displays. (Photo: Chu Chen/Xinhua)

Photo taken on Aug. 24, 2019 shows a simulated ground attack during the open day of the Australian Defence Force Academy (ADFA) in Canberra, Australia. The annual open day of the ADFA was held here on Saturday with a range of displays. (Photo: Chu Chen/Xinhua)

Photo taken on Aug. 24, 2019 shows a simulated ground attack during the open day of the Australian Defence Force Academy (ADFA) in Canberra, Australia. The annual open day of the ADFA was held here on Saturday with a range of displays. (Photo: Chu Chen/Xinhua)

Photo taken on Aug. 24, 2019 shows a tug of war game during the open day of the Australian Defence Force Academy (ADFA) in Canberra, Australia. The annual open day of the ADFA was held here on Saturday with a range of displays. (Photo: Chu Chen/Xinhua)

Photo taken on Aug. 24, 2019 shows a simulated ground attack during the open day of the Australian Defence Force Academy (ADFA) in Canberra, Australia. The annual open day of the ADFA was held here on Saturday with a range of displays. (Photo: Chu Chen/Xinhua)

Photo taken on Aug. 24, 2019 shows a band performance during the open day of the Australian Defence Force Academy (ADFA) in Canberra, Australia. The annual open day of the ADFA was held here on Saturday with a range of displays. (Photo: Chu Chen/Xinhua)

Photo taken on Aug. 24, 2019 shows a rifle spinning demonstration during the open day of the Australian Defence Force Academy (ADFA) in Canberra, Australia. The annual open day of the ADFA was held here on Saturday with a range of displays.(Photo: Chu Chen/Xinhua)