Answer:
it is very long we can't summarize in 15 words
Mecca was an important city for Arabs on the Arabian Peninsula before Islam because it was a pilgrimage site. During the 4th century, pilgrims flocked to the city of Mecca to perform an act of ritual on a small square building called Ka'aba (a cube in Arabic). Pilgrims would walk seven times around the Ka'aba to worship idols that were scattered inside the cube. Inside the cube there is also a sacred and ancient black stone that pilgrims also pay tribute to when they do their rituals in the Ka'aba.
Aside from this fact, Mecca served also as a trading post for caravans passing through the route from the Indian Ocean to the Mediterranean.
The first reason the Trans-Continental Railroad was important was because goods could now reach California from the Eastern part of our country. It also helped to open up unoccupied regions of our country that nobody was settled in. It was also a lot safer and faster to travel for people across country then by wagon train. The building of the railroad also gave the economy a boost in our country because people had to build theses railroads so people were now working.
