Vasco Núñez de Balboa is known for his exploration of the Isthmus of Panama in the early 1500s. He faced many obstacles, specifically,
D) thick jungles.
Vasco Núñez de Balboa was trying to find, what is now called the Pacific Ocean, mainly because he believed he could find gold in this area. He began his journey by crossing the Isthmus of Panama, he had to cross the thick jungles and climb mountain peaks to reach the Pacific Ocean. He was the first European explorer to see the Pacific Ocean.