The latter, measuring about 24meters by 9meters a takes its name from the large quantity of terracotta roof tiles found inside, fallen during a fire that occurred around 2200 BC which is guessed to have been caused either by lightning or by enemy raiders setting it ablaze.
A third 'first' for the site is in the use of terracotta as a building material (as there is no record of earlier such use anywhere in Greece), and yet a fourth is that the structure is the most impressive pre-Helladic structure found on the Greek mainland.
The layout is a symmetrical arrangement of smaller rooms with larger ones in the interior, with stairs leading to what was once a second storey.
The foundations were stone, the thick walls made of sun-dried brick (well preserved by being baked in the fire that destroyed the structure), and originally covered with plaster. It appears that, even after the destruction of the building, it still kept some significance.
Two Mycenaean shaft graves were dug into the ruins around 1600BC, and only at the end of the Mycenaean period (around 1250BC) was the site finally abandoned.
The chronology of this site indicates that it was not established or inhabited by Greeks.
There are some similarities in architecture and sculpture with those of Anatolia in present times, but no conclusions have yet been drawn as to who these people were.
That they were traders, however, is certain, their trade including the Aegean area and up into the Balkan peninsula.
They raised livestock, for wool and hides as well as for food, and grew all of the staple crops grown in the Argolid. Terracotta was used also in beautiful soup bowls and spoons, housed in the Argos Archaeological Museum.