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.
Pottuvil massacre happened in 2006.
Mapiripán Massacre happened in 1997.
Sinchon Massacre happened in 1950.
Glinciszki massacre happened in 1944.
Dzyatlava massacre happened in 1942.
Ranquil massacre happened in 1934.
Massacre at Béziers happened in 1209.
Boyd massacre happened in 1809.
Trelew massacre happened in 1972.