Nice idea, well implemented and at the right price too. That's the Modern Art London Underground poster by Standard Designs.
It looks like a vintage design, but this is an original by the designer, based on the 'thongs to do' posters from the Underground. This one is designed to look like an early '60s design, one that encourages beatniks to leave the coffee bars and head to the galleries.
The poster is 16.5 x 11.5 inches, professionally printed on 200gsm premium archival heavy silk paper and sold unframed (it fits a standard Ikea frame though). The price is a reasonable £16.Find out more at the Etsy website