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 Trujillo happened in 1988.
Hathikhel massacre happened in 1930.
Helmet Massacre happened in 1988.
Colfax massacre happened in 1873.
Adana massacre happened in 1909.
Chundur Massacre happened in 1991.
Massacre of Tranent happened in 1797.
Sharpeville massacre happened in 1960.
Peralta massacre happened in 1848.