Learn Spanish (Latin America): ¿Adónde viajan ustedes?

dónde means "where," but adónde specifically means "to where." Because traveling involves moving toward a destination, Spanish requires you to include that sense of motion by adding a (to) to the front of the question word. In English, we might casually say "Where are you traveling?" but Spanish is stricter about saying "To where."

Why is the verb viajan instead of viajas, since the translation says "you"?

The English word "you" can be singular or plural. Here, the speaker is asking multiple people, so they use ustedes (you all / you guys). In Latin American Spanish, ustedes always uses the same verb ending as "they." Since viajar (to travel) is an -ar verb, it takes the -an ending. If you were asking just one person informally, it would be ¿Adónde viajas tú?

Why does ustedes come after the verb viajan?

In Spanish questions, it is standard to swap the normal word order and place the subject right after the verb. While saying ¿Adónde ustedes viajan? would be understood, putting the verb first like ¿Adónde viajan ustedes? sounds much more natural to a native speaker.

Why does Adónde have an accent mark on the "o"?