sunset, sundown, sun setting = zachód słońca

Sun Setting into sea at

Source: http://www.tripadvisor.com/ShowUserReviews-g308260-d312192-r27554081-Castaway_Island_Fiji-Qalito_Island_Mamanuca_Islands.html

zachód słońca

English sentence and Polish translation

They went to the beach to watch the sunset. = Oni poszli na plażę oglądać zachód słońca.