The Barbican

I'm surprised the article doesn't mention the concert hall. It's one of London's most famous, with almost 2000 seats, and it's the London Symphony Orchestra's main home.

Until last lear, The Lead Developer conference (https://leaddev.com/) was held there, but it's moved to a larger venue for this year (I don't think the size of the main hall was the problem, it was the areas for break out etc.) They had a great talk about the history of the place: https://leaddev.com/leadership/you-are-here-the-story-of-the...

The Barbican Theatre is one of the London homes of the Royal Shakespeare Company, although they are looking to

The concert hall and theater is indeed the main reason most people who aren’t residents end up in the Barbican. When I lived in London it was almost a classical music rite of passage to get completely lost on the wrong concrete overhead walkway while rushing to get to an LSO concert there.

Unrelated, but recently the complex has been appearing in the general consciousness again as the excellent Apple TV series/spy novels Slow Horses (about a bunch of outcast MI5 agents) is set near there.