Teeny, French cafe with amazing pastries, great coffee and incredible croque-monsieur. Long table in the front and small garden in the back or take away and head to Highbury Fields, which is only a couple of minutes away.
The Royal Park offers great views of London and the city; As well as housing the Royal Observatory which includes a museum of astronomical and navigational tools, part of the National Maritime Museum.
The Greenwich Observatory with its green laser beam can transfigure any night sky. If you decide to cross the Thames via the foot tunnel, make sure you look out for the green ray. You can be on one side of the meridian in a minute, and cross to the other side on the next, without even realising it.