Architecture not for everyone but it's certainly an interesting experiment from the 1960s — enormous complex featuring a theatre, cinema, and lots of residential building.
Bancone Golden Square
Could be a full day walk: start at the King‘s Cross and walk along the Regent‘s Canal towards Regent‘s Park and then down through the park to Marylebone and swing by Monocle Cafe
Hyde Park + Kensington Gardens are also amazing for laid-back walking, swan gazing, and occasional laying down in the grass.
The Connaught Bar
Coffee and pastries in Mayfair
1rebel St Mary Axe
Regional tasty fresh food, canal vibes, beware: bushes are the bathroom.
The Design Museum
One of the best museums I've been to. Fantastic exposition — from graphic design to furniture to road signs to mobility to electronics. You can also work from there — they have wifi and plenty of tables.
Phillips Auction House
Open for all expo + auction house in the heart of Mayfair.