In Afro-Eurasia, the civilizations of the classical era built trade massive networks across land and water. Although these civilizations fell, the connections between different regions remained and expanded significantly into the post-classical era. Trade routes like the Silk Roads and the Indian Ocean trade networks saw extreme intensification and new cultural diffusion take place spreading religions and cultures along with goods and disease across borders. There was also an increase of trade across the Mediterranean network and the Trans-Saharan trade network. All of these trade connections led to the spread of goods, ideas, people, and disease across the world more than ever before.