When activated, a lever on the engine removes the tension on the rope, causing the car to drop and crush anything beneath it after which the engine immediately pulls the car back up again. The car is tied with a rope from a pulley to the engine. Car traps are makeshift traps created from a rope, a pulley, a car and an engine.The traps were engineered so that zombies could easily stumble into them and could be easily avoided by normal humans. In addition to the traps, other structures such as makeshift wooden barricades can be seen around Ravenholm, possibly to limit the herd's movement or kill them more efficiently. Due to the relative lack of ammunition in the area, Gordon must rely on Grigori's traps and the Gravity Gun from which he could launch blades, barrels and other props to use as projectiles to kill the zombies. The entire town is also littered with dead refugees and Standard Zombies that had been hanged, burned and sliced by Grigori's traps or killed by the surviving refugees of the town. Many areas of the town are littered with propane cylinders, barrels of flammable materials and Booby traps which had been laid by a lone survivor, Father Grigori. Later, Gordon is forced to escape through the town when Overwatch forces raid Black Mesa East, during the chapter "We Don't Go To Ravenholm.". As it was linked to Black Mesa East via a tunnel, the entrance to the town was sealed shortly after the bombardment using makeshift barricades and stolen Sentry Guns to prevent zombies and headcrabs from reaching the facility. The massacre resulted in the annihilation of the settlement and it was consequently abandoned. The town remained hidden from the Combine for some time, however it was eventually discovered and attacked with a massive bombardment of Headcrab Shells, slaughtering the town's inhabitants by turning them into Zombies. These buildings, along with the streets, appear in an eastern European style, complying with the style of buildings seen throughout Half-Life 2. Several high-rise apartment buildings can also be seen in some sections of the town such as the area near the coastline and the area near the room with dismembered zombies inside. The town of Ravenholm mainly consists of small to medium-sized houses that are mostly traditionally built, being made from concrete, brick, and wood.