We began to think that he will travel to meet the concerns/want to see new things/ He wants to know what's behind the mountain./ Far away in the sea?/or higher on the horizon we can see anything.
We began to think that will set out to meet the suspect / want to see new things / I know the mountain is what / how far out to sea and / or high in the sky, we see nothing.
We started thinking to depart to meet the curiosity to see new things / know then what's behind the Mountain Lu. Far out in the sea is how. Or high up in the sky, we see what.