The reason why a giant number 20 has appeared all around Glasgow city centre this week has been revealed.

The mystery was solved after the Glasgow Fort confirmed they are marking a very special milestone.

The outdoor shopping centre celebrates its 20th anniversary this month and has kick started its birthday plans.

This included sending the oversized number on tour around some of the city’s most iconic spots, including the River Clyde, Duke of Wellington statue, Glasgow Cathedral and the famous Barrowland Ballroom.

Glasgow Fort is turning 20Glasgow Fort is turning 20 (Image: Sourced)

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As well as marking 20 years of welcoming customers to the popular shopping destination, the large visual was also a way for Glasgow Fort to say thank you to the community for its continued support.

Those who saw the sign travelling through Glasgow were able to scan a QR code to be in with the chance of winning £2,000 worth of vouchers to spend at the centre’s retailers and restaurants.

Those who missed the sign will still have a chance to win, with the giant ‘20’ now located at Glasgow Fort – where the centre’s birthday celebrations continue throughout October – until Sunday, October 27.

Marks & Spencer’s iconic birthday mascot, Colin the Caterpillar, will also be visiting the centre on Monday to host a birthday treasure hunt.

The giant 20 has been travelling the around city The giant 20 has been travelling the around city (Image: Sourced)

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There will also be a celebration on Saturday, including live music and performances from acts such as an LED drummer, dancers and a DJ.

Phil Goodman, centre director at Glasgow Fort, said: “This week we kickstarted our 20th anniversary celebrations with a tour around iconic locations in Glasgow launching our big competition to give back to those that have supported us over the years. “With a whole host of additional activities planned over the next few weeks – from the Colin the Caterpillar Hunt to a big birthday bash – we’re excited to invite everyone to mark this milestone with us.”