A minor error has been noted. The first line should be Moscow. The puzzle as shown is correct.
The final answer is a single word.
January 18
The world ended today. Not with a bang, but a whimper–it sounds so cliché, but it's the only way to describe what happened. All our preparations were for naught because the elite team we assembled to fight for us were too busy playing around instead of taking action.
I've compiled a list of when our operatives called us this morning to report the bad news. When Washington reported that they had fallen, I knew it was all over and that humanity had lost. Hopefully this record will help future civilizations piece together what happened and realize that inaction is not the answer.
– Brenda F.
Text version:
Moscow
Milan
Lagos
Essen
Tokyo
Hong Kong
Atlanta
Seoul
Khartoum
Beijing
San Francisco
Cairo
London
Buenos Aires
Sydney
Chennai
Cairo
London
San Francisco
Khartoum
Milan
Seoul
Hong Kong
Buenos Aires
Sydney
Beijing
Mexico City
Mexico City
Sydney
Karachi
Sydney
Mexico City
Karachi
London
Seoul
Khartoum
Chennai
Cairo
Hong Kong
San Francisco
Beijing
Buenos Aires
Washington
Washington
Hint 1:
Either the text version or the picture version could provide the needed information for the puzzle on their own.