The world surpassed two sobering COVID-19 milestones on Sunday — 5,00,000 confirmed deaths, 10 million cases — and hit another high mark for daily new infections as governments that attempted re-openings continued to backtrack and warn that worse news could be yet to come.

Re-openings were rolled back in Texas, California, Florida where the governor said interactions among young people are driving the surge. For months, experts have warned of a potential nightmare scenario: After overwhelming health systems in some of the world's wealthiest regions, the COVID-19 gains a foothold in poor or war-torn countries ill-equipped to contain it.