Cave of the Patriarchs massacre happened on 1994-02-25.
Goyang Geumjeong Cave Massacre happened on 1950-10-09.
In Hebron, Israel.
Yes. Muslims can pray at Abraham's tomb. Currently there is a schedule when Jews can use the Cave of the Patriarchs and when Muslims can use it. However, it is worth noting that the Cave of the Patriarchs is in Hebron, which is part of the Palestinian West Bank and is not a sovereign part of Israel.
Massacre of Kondomari happened in 1941.
Bleiburg massacre happened in 1945.
Aranthalawa Massacre happened in 1987.
Palawan Massacre happened in 1945.
Kucheng Massacre happened in 1895.
Kibeho Massacre happened in 1995.
Itaba massacre happened in 2002.
Thalit massacre happened in 1997.
Lovas massacre happened in 1991.