Bald Cypress with Knees in Schwerin Palace Park

Bald cypress, Taxodium distichum, stands close to the water and has therefore developed strong aerial roots, known as knees.Source: garten-tour.de/gaerten-und-parks-l-z/schwerin/index.html

There are a few bald cypresses in the park. But only those whose feet flood from time to time form these roots above the earth. This is how adventitious roots form.

Really fascinating trees...
Breathing knees, knee roots, or aerial knees are formed by some swamp and mangrove trees. They break through the soil surface as root loops or negatively gravitropic (growing in the opposite direction of gravity) outgrowths of the horizontally oriented, near-surface subterranean root system. Respiratory knees serve as pneumatophores; their aerenchyma (aeration tissue) ensures the gas exchange of the subterranean root system in the oxygen-poor sediment.
(Wikipedia)