Denmark has won praise from Sen. Bernie Sanders (I-Vt.) and other left-wing politicians for its socialist policies. Its latest project, however, seems like it could have come straight from the playbook of President Trump. Fearing the spread of African swine fever, the country began erecting its own southern border wall Monday. Or, perhaps, a boar(der) wall. The 43-mile-long steel-mat fence will stand five feet tall and extend across the Danish-German border.