Homeward bound

Where could this possibly be?
The green park is very green - no flowers, no buildings, and few monuments. Unfortunately the bit I see on my daily commute underground is the exact opposite!

Royalparks.org.uk does have an interesting snippet about the name though, so, in the absence of any juicy information:

In 1746, Upper St James 's was officially renamed The Green Park. We don't know the exact reason for the new name. It may be because, at the time, the park was an open meadow with few trees. Or it may date back to a tale about King Charles II and his wife. Apparently, she discovered that Charles had picked flowers in the park and given them to another woman. In revenge, the Queen ordered that every single flower in the park should be pulled up and no more planted. True or not, there are still no formal flowerbeds in The Green Park.