Final answer:
The completion of the Key West Extension was a big deal because it facilitated westward expansion, created economic opportunities, and demonstrated impressive engineering achievements.
Step-by-step explanation:
Completing the Key West Extension was such a big deal because it played a significant role in the transportation developments in the first half of the nineteenth century, specifically for westward expansion.
The extension connected the Florida Keys to the mainland, making it easier for people and goods to travel to and from the area. It also had important economic implications, as it opened up new trade routes and opportunities for the region.
Moreover, the Key West Extension was part of the larger project of building the Overseas Railroad, which was an engineering marvel of its time.
The construction of the railroad involved overcoming numerous challenges, such as building bridges over the water and dealing with the harsh climate. The completion of this ambitious project showcased the technological advancements of the era.
In summary, the completion of the Key West Extension was a big deal because it facilitated westward expansion, created economic opportunities, and demonstrated impressive engineering achievements.