This is the 6087th most frequent Turkish word.
yaşadıkları
"Yaşadıkları" means "what they experienced" or "what they lived through."
Here, 'yaşadıkları' is derived from 'yaşamak' and is a verbal adjective meaning 'that they live'. It modifies 'şehir', showing the city associated with their living.
Onların yaşadıkları şehir çok sessiz.
The city they live in is very quiet.
In this sentence, 'yaşadıkları' comes from 'yaşamak' and refers to 'the things they experienced'. It acts as a noun, thus serving as the subject of the verb 'değiştirdi'.
O yıllarda yaşadıkları olaylar onun hayatını değiştirdi.
The events they experienced during those years changed their life.
Here, 'yaşadıkları' again is derived from 'yaşamak' and means 'that they lived'. It describes 'ev', denoting the house associated with their living.