Complex sentence: Another significant Kidan city was Bars-Hot existed in the basin of the river Kerulen, occupying an area of 1600 x 1810 metros, surrounded with mud walls which are today 4 metres thick and 1.5--2 metres high.
Split into simpler sentences: Another significant Kidan city was Bars-Hot, located in the basin of the river Kerulen, occupying an area of 1600 by 1810 metres. The city was surrounded with mud walls which are today 4 metres thick and 1.5--2 metres high.