I think i may have outdone myself here, (takes a bow)

Some sections (less than 5% of total length) are constructed as a wall made up of concrete slabs up to 8 m in height and 3 m in width. ...
Wall construction (5%) is more common in urban settings, such as areas near Qalqilyah and Jerusalem, because it is narrower, requires less land, and provides more protection against snipers.
en.wikipedia.org...