Senar is the estate of the Russian composer Sergei Rachmaninoff, located in Switzerland, in the village of Hertenstein, municipality of Weggis, Lucerne canton, on the shores of Lake Lucerne with a view of Mount Pilatus.

The villa includes two houses, 10 hectares of land with a garden, a promenade, and a dock. The name 'Senar' is formed from the first letters of the names of the Rachmaninoff spouses, Sergei and Natalia, as well as the first letter of their surname.

At this estate, Rachmaninoff wrote one of his most famous works, Rhapsody on a Theme of Paganini.

The composer, who emigrated to the USA, first visited Switzerland in 1930. He purchased a plot in the village of Hertenstein near Lucerne, covering 10 hectares, with a view of Lake Lucerne and Mount Pilatus, and began constructing the villa 'Senar'. He lived here from the summer of 1932 until 1940.

The layout of the villa and the two-story estate house was designed in a nostalgic style reminiscent of his estate in Ivanovka (Tambov region), with a garden where the same trees grew: apple trees, maples, and chestnuts.

After the composer's death in 1943, the estate passed to his heirs: first to his second daughter Tatiana, then to his grandson Alexander Rachmaninoff (1933, 2012), who established the S. V. Rachmaninoff Foundation.

By 2013, 'Senar' preserved the original furnishings, furniture, musical instruments, including a Steinway piano gifted to the composer by W. Steinway, as well as unique items of Rachmaninoff's cultural heritage: diaries, scores, correspondence, and archives.