What two european countries had the most impact
on the new world?

England and Spain

Explanation:

During age of exploration, Many European countries invested heavily in the sailors & explorers with the hope that they would come back with new information that could benefit their country. (such as new land to obtain natural resources or new trade routes).

Compared to other Europeans, England and Spain are considered to be the most successful in their effort.

They managed to colonize a lot of regions and make local people learn  their cultures, Religion, language, and political system.

One of the  proof of this could be seen in the most spoken language today. If we only count the language that spoken by people outside their country of origin, English and Spanish Language ranked 1st and 2nd .

explanation:

may i ask what challenges?