

O mundo é muito grande.
Quero viajar pelo mundo todo.
Qual é o maior país do mundo?
"o mundo" is in the lesson "Geography" (Level 22), along with 9 other useful words. LinDuo has 180 topic lessons like this one, 2,380 words in total. Every word has an illustration, a transcription and pronunciation in a female and a male voice. Just 10–15 minutes a day is enough to learn them all. Free, and works offline.