Question

Combine these simple sentences using at least one gerund phrase. Pablo traveled. He went to Lima, Peru. He visited a museum. He learned about the Incas.

Answer 1

The answer to your question would be that a way to combine the sentences using at least one gerund phrase is the following one: When travelling, Pablo went to Lima, Peru; visited a museum and learned about the Incas.

This is a reduced time-related clause because it is a gerund phrase as the subject of both clauses is the same: Pablo is the one who travelled and the one who went to Lima and visited a museum.

Answer 2

Ok I'm peruvian, I got exited lol. 
 Pablo was traveling to Lima, Peru. As he visited the museum, he was learning about the Incas.