TIJUANA — On the imposing metal sheets of the border fence that divides Tijuana, Mexico from San Diego, California, a hand reaches out in friendship amid a burst of butterflies.

Nearby, in darker tones, a pile of skulls is crowned by a steely cross.

This massive meditation on humanity at its best and worst is the work of Mexican artist Enrique Chiu, who is seeking to set a Guinness World Record for the longest mural ever painted.

Named the "Mural of Brotherhood," the painting is nearly two kilometers (a mile and a quarter) long.

And Chiu’s canvas could get a lot bigger if US President Donald Trump gets his way: his planned border wall would stretch some 1,600 kilometers.

The current world record holder for the largest outdoor mural is in the US state of Colorado and measures 3.2 kilometres long and more than 17 metres high.

Chiu is not alone in his quixotic project to set a world record covering the border wall in art.

Some 2,000 residents of the border region have contributed to the project, painting pictures, words or simply leaving their handprints on a long section of the various types of wall and fencing that already cover about one-third of the 3,200-kilometre border.

"It’s a project that seeks to create a link between art and society. It’s about making an artistic, social mural, in which people can come and express whatever they want, whatever is on their minds, their experience of life on the border," said Chiu.

The project, which started last December, contains a wide array of styles, from professional artists’ paintbrushes to urban taggers’ graffiti.

Those with less artistic flair have covered the wall in words like "unity," "equality," "art" and "freedom," in both Spanish and English.

One of the most oft-repeated messages is: "#NoWalls." — AFP