The Chestnut Avenue was planted at the time of the Spanish Armada when a small number of nuts that floated up the Estuary, were gathered by the triumphal peasantry, and planted to celebrate their delivery from the Catholic Hordes. Looked at closely the gnarled and venerable trees reveal a small and active community of very small people living off the detritus.Nearby is Floyer's door of which a particular study has been made, together with several revealing Family Snaps.
One of the trees can be used for access to the Water under the Ground. If you tire or become alarmed you can always leg it by using the usual exit door. Persevere and you will get to Astley's Amazing Aquarium, well worth a visit.
The details are included to encourage you to take seriously the magnificent Boles several of which contain cities and runways.
To the left there is another stretch of the Avenue and access to Floyer's door.
An instructive text from 1791 may help your understanding.