Our Lady Star of the Sea and St Winefride (Welsh: Mair, Seren Y Mor a Santes Wenfrewi[1]) is a Roman Catholic church in Amlwch, a town on the island of Anglesey, north Wales.

[6] The architect was Giuseppe Rinvolucri, an Italian engineer from Piedmont, who settled in Conwy, north Wales, because his English wife was suffering from tuberculosis.

His specialist field was the design of Roman Catholic churches, and other – more conventional – examples of his work can be found in Abergele and Porthmadog, also in north Wales.

[1] Damage from the weather and deterioration in the concrete meant that the church closed for worship in 2004, requiring worshippers to attend services elsewhere on Anglesey.

The ribs on the outside are visible inside the building; in between them, there are patterns of lights and coloured marble panels on the lower parts of the interior walls.

[3] Cadw describes it as "striking and individual", and "a highly unusual and experimental design which exploits the plastic qualities of its constructional material to create a powerfully expressive religious building.

He noted the "sweeping parabolic arches, perhaps inspired by airship hangars or by upturned boats in Amlwch harbour", as well as the "bold gable with sloping sides" at the west end, concluding "This church must be saved.

[4] It noted the "highly individual interpretation of its seaside setting", with a "strikingly modern" parabolic design and a "monumental almost pyramidal aesthetic" at the entrance.