Norwich joined several other cities around the country in lighting up a significant building to mark 250 years since the birth of circus.
The event was held to mark the date when showman, equestrian and entrepreneur Philip Astley drew out a ring on January 9, 1768.
He filled it with astonishing acts including tumblers, horses, acrobats, jugglers and clowns and in doing so created the first circus.
Every circus, anywhere in the world, has its roots in that moment.
On Tuesday night the side of Norwich Castle was lit up with a Sir Peter Blake Circus250 logo from 4pm to 10pm as the city joined Blackpool, Derry, Great Yarmouth, Bristol and Newcastle-under-Lyme in celebration of the event.
In Great Yarmouth, the Hippodrome Circus was illuminated with the logo while in London, a special circus performance at the Creative Industries Federation' third anniversary celebration in the Natural History Museum took place.
Norwich is the birthplace of famous 19th century black circus proprietor Pablo Fanque and The Lord Mayor's Celebrations features a circus parade with life-sized elephant puppets winding through the streets.
The Hippodrome is Britain's only surviving complete circus building and produces four world class circus shows, with its Summer Spectacular themed around the Circus250 celebrations.
Producer and director of the Hippodrome's annual productions, Jack Jay, said they had 'big, big plans' for 2018 and the 250th anniversary of circus.
He said: Our Summer Spectacular will be specially written to incorporate both the historical elements of the birth of circus but also the vibrant nature of the current circus world.'
Sir Tony Robinson, actor, historian, broadcaster and Circus250 Champion, said it was wonderful to see 250 years of circus being celebrated in the country.
'Actors like me are influenced by circus, alongside artists, filmmakers, comedians, mime artists and writers,' he said.
'It has a proud past, vibrant present, and, I'm certain, a fabulous future. It's also huge fun.
'Circus250 in 2018 isn't only going to be the greatest show, it's going to be the best fun.'
Circus250 is the Community Interest Company coordinating the celebration of 250 years of circus in 2018.
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