How could the geographic location of the Triple Alliance and the Triple Entente lead to a war involving all of Europe?

Well countries typically allied with their neighbors because they usually had close relations like for instance Britain France and Belgium where all huddled together in west Europe while Germany was close to with Austria Hungary and both had good relations with the ottoman empire. because all of these countries were close together sometimes things got heated and with all of these alliances it was easy for all of these countries to fight each other.