The blast wall, a 15-foot high concrete barrier, shaped like an upside-down letter T, is on the left. Its counterpart, the Hesco barrier, is on the right. A Hesco is a folding metal basket with a paper liner filled with dirt.
The advantage of the Hescos is that you can ship them broken down and fill them where you need them. The blast walls, on the other hand, are more durable and look nicer.
This picture is from right outside the recreation center where I am holed up afternoons to use the internet.