These ruins represent the height of Birrin pre-industrial engineering, and continue to impress tourists from more recent, technologically complex societies today.
Part city and part fortress, this gate was built to defend one of the few entrances to a lush, steep walled floatforest valley beyond, in which a society of several million inhabitants flourished for centuries.
Initially a natural stone monolith with only a narrow passageway dividing it, generations of craftspeople and slaves hammered away at the stone to perfect it into its current form, before finally coating it with a resin/sand mixture to protect it from further natural erosion.
The guardian statues warned foreign armies and traders of the power and capabilities of the valley people, who maintained a massive standing army at all times, based in a garrisons built into the gate walls.
Too heavy to themselves be created from stone, the guardian statues were built from the interlaced and cemented trunks and roots of local float-forest and other imported plants. Treated with resin to prevent decay, this meshwork was then coated in the same substance used to smooth the wall standing behind them.
Ultimately, the civilisation responsible was conquered by a society that had developed steam powered warships, and who attacked from one of the seaward entrances of the valley.
Left to ruin by the conquerors for several centuries, it is now of prime interest to archaeologists attempting to reconstruct the history of the valley society.
Seen here, a small camp of nomadic locals pitch tents in the evening glow of the great gate.