Photographers from around the world have been busy capturing a lunar lightshow - the blue supermoon.
A supermoon occurs when a full moon rises during its closest point in its orbit to Earth.
A blue moon is even rarer, happening when there are two full moons within a single calendar month or four full moons within a season.
It happens once every two to three years - that's where the saying "once in a blue moon" comes from.
The dust from wildfires in North America may give the moon a red glow; blue moons aren't actually blue.
During a supermoon, the moon appears up to 14% bigger and 30% brighter compared with when it is furthest away.
After this supermoon, the next will be on 18 September, followed by 17 October and then finishing with a final supermoon on 15 November.
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While Monday's blue supermoon is rare, September's coincides with a partial lunar eclipse - another sight worth watching out for.
The term supermoon was coined by astrologer Richard Nolle in 1979 as either a new or full moon that occurs when the moon is within 90% of its closest approach to Earth.