Donald Trump has given some intriguing insights into what he believes the much-anticipated but highly controversial border wall between the US and Mexico could look like.

Trump revealed much of the information in comments made on his flight to Paris to visit French President Emmanuel Macron.

The White House had originally said his comments were off the record, but it later reversed that decision – and so here’s what the wall might look like.

It will cover less than half the border

Trump and Melania
(Carolyn Kaster/AP)

Although the border between the two countries stretches roughly 2,000 miles, Trump told reporters on Air Force One the US only needs “anywhere from 700 to 900 miles” of wall.

He said this is due to the presence of “natural barriers” such as mountains and rivers, like the Rio Grande bordering Texas or the Colorado River on the border of Arizona.

He described the rivers as “violent and vicious”, although parts of the river in Texas are little more than a trickle of water.

Trump’s comments on the size of the wall have been met with some scorn.

Trump also claimed some areas are so “far away” that “you don’t really have people crossing”.

There are currently about 650 miles of fencing along the border, so the wall may not be as significant an increase in the length of the border barriers as previously thought.

It might be transparent

France Trump
(Markus Schreiber/AP)

“You have to be able to see through it,” Trump said.

The reason offered? To avoid border agents being hit by sacks of drugs or other contraband thrown from the other side.

“As horrible as it sounds, when they throw the large sacks of drugs over, and if you have people on the other side of the wall, you don’t see them,” Trump said. “They hit you on the head with 60 pounds (27 kilograms) of stuff? It’s over.”

Drug smugglers have in the past tried to hurl bundles over parts of the border fence using sling shots and catapults.

However, it’s not clear if anyone has ever been injured by such tactics.

It could have solar panels

France Bastille Day
(Markus Schreiber/AP)

Trump told a rally in Iowa last month the wall could feature solar panels – allowing it to “create energy and pay for itself”.

By “pay for itself” he didn’t necessarily mean helping the US, though. He joked it would mean Mexico – which he has repeatedly said will fund the build – “will have to pay much less money” towards the structure.

The Mexican government has rejected the possibility of paying for the wall.

Trump also claimed the panels would make the wall “beautiful”, praising himself by saying: “Pretty good imagination, right?”

Trump’s official visit to France continues. On Thursday night he shared a meal with Mr Macron and his wife Brigitte at the Eiffel Tower. Trump will attend the Bastille Day celebrations as a guest of honour on Friday.