Chile's foreign population has risen sharply in the past decade, jumping from less than 600,000 in 2015 to more than 1. 5 million in 2024, according to World Bank data. Its government estimates that about 336,000 of these are undocumented migrants, many from Venezuela. The trench-digging on Monday marks the start of the "border shield" promise that helped Kast win the presidency by 58% in December. The nation's border with Peru spans around 180km and a further 900km with Bolivia - though its interior ministry has said the barrier will only cover roughly half of this. The election of Kast, who succeeded left-winger Gabriel Boric as president, marks the nation's most abrupt rightward shift since the end of its military dictatorship in 1990.