Customs and Border Protection released video Tuesday of construction of border wall prototypes on the southern border.

Construct on eight types of border wall prototypes began Tuesday. All four will be between 18 and 30 feet high. Four will be made of concrete, while the others are made of alternate material. They are expected to be completed within 30 days.

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The prototypes were supposed to start being built in June, but the process was delayed due to protests from a bidder. President Trump campaigned on building a border wall, but has faced difficulty getting funding from Congress. Instead, a sea-to-sea wall, it is now looking like it will be constructing in the areas that need a barrier the most.

“You have a lot of natural barriers, et cetera. Somebody said, ‘Well, what are you going to do, you going to build that wall in the middle of the river? … That nobody can go in? Are you going to build that wall on the mountain?’ I said, ‘You don’t need the wall on the mountain. You have a mountain which is a wall,'” Trump said at a recent rally. “But we are going to build a wall. It is coming along great.”