The Hall of Diplomacy was a governmental building on the Kreetassan homeworld, Kreetassa. Outside the Hall were a stand of alvera trees which, by 2152, were over 300 years old and which the Kreetassans considered a cultural treasure.
In 2152, Porthos urinated on one of the alvera trees outside the Hall of Diplomacy. Upon revisiting Kreetassa shortly thereafter, the dog's owner, Captain Jonathan Archer performed ritual sectioning of an alvera tree – required by the Kreetassans as an apology – outside the Hall. (ENT: "A Night in Sickbay")