_________the Confederations World Cup (a warm up tournament for 2014 football World Cup) went on, hundreds of thousands of Brazilians took to the streets of São Paulo, Rio de Janeiro, Porto Alegre, Belo Horizonte and many other major, cities in Brazil
1 Answer
If you want meanwhile to make sense in this sentence, there needs to be a preceding action or event. As a stand alone sentence using meanwhile sounds awkward here. On the other hand "While" sounds fine if the sentence is stand alone.