The Liepāja massacres were a series of mass executions, many in public or semi-public, in and near the city of Liepāja (German: Libau), on the west coast of Latvia in 1941 after the Nazi occupation of Latvia. The main perpetrators were detachments of the Einsatzgruppen, the Sicherheitsdienst or SD, the Ordnungspolizei, or ORPO, and Latvian auxiliary police and militia forces. Wehrmacht and German naval forces participated in the shootings. In addition to Jews, the Nazis and their Latvian collaborators also killed Gypsies, communists, the mentally ill and so-called ""hostages"". In contrast to most other Holocaust murders in Latvia, the killings at Liepāja were done in open places. About 5,000 of the 5,700 Jews trapped in Liepāja were shot, most of them in 1941. The killings occurred at a variety of places within and outside of the city, including Rainis Park in the city center, and areas near the harbor, the Olympic Stadium, and the lighthouse. The largest massacre, of 2731 Jews, and 23 communists, happened from December 15 to 17, 1941, in the dunes near Šķēde, on an old Latvian army training ground. More is known about the killing of the Jews of Liepāja than in any other city in Latvia except for Riga.