I fondly remember way back when they featured Poems on the Underground, reading a couple that seem to have stayed with me.
One fine day, I found myself on a platform trying to get a Mars bar from one of the vending machines, when I happened to look up and see the following poem.

I May, I Might, I Must

If you will tell me why the fen
appears impassable, I then
will tell you why I think that I
can get across it if I try.

Marianne Moore

While they are handy for keeping the crows away, and not quite as effective at mole removal, I couldn’t help but raise a smile when I read the following poem on the District Line to Putney Bridge:

Ode to a Scarecrow

Hey, be seedy! He effigy, hate-shy, jakey yellow man. Oh pique! You are rusty, you’ve double, you ex-wise head.

Unknown

Poems on the Underground was introduced in 1986 as a means of bringing poetry to a wider audience and was the brainchild of Judith Chernaik, an American writer.