The Küçük Hasan Pasha Mosque or Gialisi Tzami (mosque of the sea) is actually the only preserved mosque of the city of Chania. It was built on the site of a preexisting Christian temple after the conquest of Chania by the Ottomans in 1645, honoring Küçük Hasan Pasha.
The mosque bears a large semispherical dome supported by stone arches. The north and west sides house a gallery that is topped by six small domes. This gallery was initially open, as used in the mosques, but in the late 19th century it was closed by arched openings.
The mosque was a project of the same Armenian architect that built the mosque of Spaniakos, near Paleochora. The mosque was surrounded by a nice yard with tall palm trees, which hosted the graves of the Ottoman rulers. It ceased its operation in 1923 and its minaret was demolished in 1939.
During the 2nd World War it housed the Archaeological Museum of Chania. Afterwards it was used as a storehouse, folklore museum, tourist information point and exhibition venue.