Nemesis (code name Secret weapon 3) is an inverted roller coaster located at the Alton Towers amusement park in England. The ride's concept and layout was devised by designer John Wardley.
It was manufactured by Bolliger & Mabillard (B&M) and opened in 1994. It is located in the Forbidden Valley area of the park, adjacent to Air, a flying B&M roller coaster that opened in 2002.
Once the train is locked and checked, it departs the station making a 45-degree, right-hand turn towards the lift hill. Once at the top of the 13-metre (43 ft) hill, the train makes a small dip and turns around 180 degrees to the left. The train then descends 31.7 metres (104 ft) down the first drop into the first inversion, a right-handed corkscrew.
The train then navigates a right-handed, 270-degree downward helix that features 90 degree banking. Then the train rises up into the second inversion, a zero-g roll, where riders experience the feeling of weightlessness. It then makes a 180-degree right-handed stall turn into the third inversion, a vertical loop. After a left stall turn the train enters the second corkscrew. The train then passes through an underground tunnel, and through one more 180-degree turn, before being stopped by the brake run and returning to the station