 A medieval village lay near Tobar Childa , about 350 metres ( 1 @,@ 150 ft ) from the shore , at the foot of the slopes of Conachair . The oldest building is an underground passage with two small annexes called Taigh an t @-@ Sithiche ( house of the faeries ) which dates to between 500 BC and 300 AD . The St Kildans believed it was a house or hiding place , although a more recent theory suggests that it was an ice house . 
