I think this would be the Great Wall of China!
although it's actually thought to be much, much longer: over 5000 miles long, if yoiu include natural defensive barriers used in it.
Answer:
from water to land - high to low pressure
Explanation:
Oil still plays an important role in the global economy despite the continued efforts to reduce its use and to find alternative green energy sources. In the early days, finding oil during a drill was considered somewhat of a nuisance as the intended treasures were normally water or salt. It wasn't until 1847 that the first commercial oil well was drilled in the Absheron Peninsula, Azerbaijan.1 The U.S. petroleum industry was born 12 years later, in 1859, with intentional drilling near Titusville, Pennsylvania. (Drilling in the United States began in the early 1800s, but they were drilling for brine so any oil discovery was accidental.)2
Islam became part of North African cultures due to the geographical location and due to the spread of refugees from Saudi Arabia and other countries in Asia. North Africa was one of the first countries that Islam spread to other than Asia.
