The Divided World

 60 years ago in August 1961, the Berlin Wall was constructed. The aim was to prevent people from fleeing the then German Democratic Republic (GDR). At least 2.6 million people had already done so since its founding in 1949. They sought better lives across the border in West Germany, which was officially known as the Federal Republic of Germany (FRG).

Between 2000 and 2021, the number of completed, started or announced border walls or fences in the world more than quintupled, from 16 to more than 90.

 Studies are divided on whether walls can prevent irregular migration.

 "There's no scientific consensus, which means that walls are not universally effective at deterring immigration," Sergi Pardos-Prado, a political scientist at the University of Glasgow, wrote to DW in an email. "Sometimes migration finds alternative routes ­— sea or alternative, indirect land connections. Walls are slow and expensive constructions, sometimes you prevent access in a specific area but you incentivize access in a different area still under construction or less robust. It is rare to find a perfect, massive, solid, impenetrable block covering the whole length of the border."

Economist Klaus Zimmermann wrote in an email to DW that most social scientists working in the migration field "think that it is not a reasonable instrument." Border barriers are "mostly a political showcase for policymakers to impress voters in the short term," Zimmerman concluded.