See the Deer in Greenwich park
You can escape the hetic city streets and find something more peaceful!
I have lived in London for many years without knowing there is actually a Deer area in Greenwich park. There are two viewing locations and to complete this challenge you must register your location at each of the two locations.

You have to complete both stages within 12 hours but 30 minutes is easily enough.
Start with small viewing area

There are two viewing areas for the same deer enclosure and you will have to find both of them to complete this challenge. The smaller one is first. You can spot the deer from here but it’s likely they will be far away.
Then move to large viewing area

The second viewing area is better. There is more seating here, better views of the deer as well but you still have to squint.