AWP Tokyo v3 - Sniper War. By binska. Have Fun! AWP_tokyo map inspired by Tokyo drainage/sewer system! It’s simply an engineering marvel, and unquestionably one of the most awe-inspiring wonder spots of Japan. It has been described as “the concrete junkie’s equivalent to a dropper of heroin”. And it lies hidden underneath the outskirts of metropolitan Tokyo. The aim was simple: to take all the excess rainwater from typhoons and floods away before it can cause any damage. The way it was implemented is also simple – they built a big drain. But the enormity and engineering complexity of the construction is staggering. During heavy rains and typhoons, tons and tons of flood and rainwater pours down these sinkholes and falls into the next engineering marvel – a giant concrete pipeline acting as an “underground river” which transports the water more than 6.3km through a tunnel 50m underneath the river basin.