This is what we found on Wikipedia regarding the Arena Cross World Tour Finals at Etihad Arena:

Manchester Arena (currently known as AO Arena for sponsorship reasons) is an indoor arena in Manchester, England, immediately north of the city centre and partly above Manchester Victoria railway station in air rights space. With a capacity of 23,000 it is the second largest indoor arena in the UK after Co-op Live and third largest in Europe.

The arena is one of the world's busiest indoor arenas, hosting music and sporting events such as boxing and swimming. The arena was a key part of Manchester's bids to host the Olympic Games in 1996 and 2000 and was eventually used for the 2002 Commonwealth Games.

On 22 May 2017, the arena's foyer was the scene of a terrorist attack carried out by a suicide bomber, in which 22 people were killed and 1,017 injured following an Ariana Grande concert.