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MIAMI (CBSMiami) — President Donald Trump is one step closer to building his much promised border wall.

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Thursday was the deadline for contractors to finish building their prototypes.

Eight massive walls sit near a border crossing between California and Mexico.

Six different construction companies built the prototypes for Trump’s proposed southern border wall.

“These prototypes are vitally important for the future of border security here in SD as well as the southwest border,” said Ronald Vitiello, CBP Acting Deputy Commissioner.

Each life-size model costs between $300,000 to half a million dollars.

Four are made of concrete and the rest are concrete and other materials including steel.

The height requirement was between 18 to 30 feet but they all meet the maximum with varying designs including rounded tops and one with steel mesh and spikes.

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The next step is to begin testing the walls to see how each one can handle being climbed over, cut through and dug underneath.

“We’re going to look at all of these features, look at what works and doesn’t work,” said Vitiello.

Two are constructed with slats on the bottom, giving visibility of the other side.

Environmentalists have raised questions about a solid wall preventing animal migration.

Right now, a decades-old fencing runs along about a third of the 1,900-mile U.S.- Mexico border.

Last year, border patrol agents detained more than 31,000 people and seized thousands of pounds of illegal drugs.

Officials say the final decision could be one or a combination of several or even all of the designs and materials.

It remains to be seen whether Congress will approve the $1.6 billion needed to start building the new wall.

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The total tab could run more than $ 21 billion.