Answer:
When Austria-Hungary declared war on Serbia, it led to Russia declaring war on Austria-Hungary as well because Russia was in an alliance with Serbia.
Germany which had an alliance with Austria-Hungary via the Triple Alliance then declared war on Russia.
Russia was already in an alliance with Great Britain and France known as the Triple Entente and when Germany declared war on Russia, Great Britain and France declared war on Germany.
Thus began the Great War.
There were multiple reasons the War of 1812 happened, one of them being that Britain and France were battling, which caused Britain to restrict French trade from the United States, which didn't make Americans happy. Another reason was the United Kingdom didn't want the United States to expand and become powerful, as they may be deemed as a threat, so they supported Natives in keeping their land so Americans couldn't expand. The last reason I know of, was Britain would capture some of our troops and force them to join their army. These things lead to the War of 1812, which was followed by peace between the United Kingdom and the United States.
According to my research, Mecca is the correct answer.
