Question: In 2001, Six Flags bought the theme park that was adjacent to Six Flags Ohio. What year did this originally open?

Context articles: SeaWorld Ohio
Six Flags Over Texas
Six Flags Zhejiang
The Joker (S&amp;S Worldwide)
Six Flags Dubai
Thunderbolt (Six Flags New England)
Geauga Lake
Six Flags México
Six Flags Discovery Kingdom
Roar (roller coaster)

SeaWorld Ohio was a park in the SeaWorld chain of marine animal theme parks.
 The park opened in 1970 directly across the lake and less than one mile from Geauga Lake Park in Aurora, Ohio, United States.
 The small lake separated the two parks.
 Wildwater Kingdom, a small waterpark built by Cedar Fair in 2005, occupied the property until it closed in 2016.
Six Flags Over Texas is a 212-acre (86 ha) theme park located in Arlington, Texas, east of Fort Worth and about 15 miles (24 km) west of Dallas.
 It was the first Six Flags Theme Park, but because of later acquisitions it is not the oldest park of the Six Flags chain (that particular title is held by Six Flags New England).
 The park opened on August 5, 1961, following just a year of construction and an initial investment of US$10 million by real estate developer Angus G. Wynne, Jr.
Six Flags Zhejiang is an upcoming amusement park at Jiaxing, Zhejiang, China, owned by Six Flags.
 It will feature original rides and attractions, along with attractions themed around "Garfield and Friends".
 In addition to a theme park, the park will be accompanied by a Six Flags Hurricane Harbor water park.
The Joker is a roller coaster located at Six Flags Great Adventure, Six Flags Great America, Six Flags New England, and Six Flags Over Texas.
 Built by S&S Worldwide, an American ride manufacturer, the coaster is one of their "Free Spin" models.
 Since 2016, Six Flags has installed The Joker in four of their parks.
Six Flags Dubai is a theme park being built in United Arab Emirates by Tatweer Dubai LLC under a licensing agreement with Six Flags.
 The park was scheduled to open in November 2011, but Six Flags terminated the agreement in 2010 after Tatweer failed to make a payment owed to Six Flags.
 It was later revived and is scheduled to open in 2019 near Lapita Hotel and Riverland Dubai at Dubai Parks and Resorts.
Thunderbolt is a wooden roller coaster located at Six Flags New England.
 Opened in 1941, It was designed by Harry Baker and Harry Traver, and built by Joseph Drambour.
 Thunderbolt is the oldest roller coaster at Six Flags New England.
 It is also the oldest roller coaster in any Six Flags park (the Wild One at Six Flags America was built in 1917, but it was relocated from Paragon Park and has only been at Six Flags America since 1986).
 The single PTC train has 4 cars, and an individual lap bar and seatbelt for each person.
 An attendant has to manually unlock each car's lap bars by stepping on and pushing down a release bar at the front of each car.
 Thunderbolt was dedicated an ACE Coaster Landmark on August 2, 2008.
Geauga Lake is an abandoned theme park in Bainbridge Township and Aurora, Ohio, United States.
 Established in 1887 in what had been a local recreation area adjacent to a lake of the same name, the first amusement ride was added in 1889, and the park's first roller coaster – later known as the Big Dipper – was built in 1925.
 In 1969, the park was sold to Funtime, Inc., and was expanded over the years with additional rides and amenities.
 Further expansion occurred in the mid and late 1990s after Funtime's acquisition by Premier Parks in 1995.
 Prior to the 2000 season, soon after Premier Parks acquired Six Flags, the park was re-branded as Six Flags Ohio and four new roller coasters were added.
 A year later, Six Flags bought the adjacent SeaWorld Ohio and combined the two parks under the name Six Flags Worlds of Adventure.
Six Flags México is an amusement park located in the Tlalpan forest and borough, on the southern edge of Mexico City, Mexico.
 It is owned and operated by Six Flags Inc. and the only Six Flags park operating in Latin America.
 It is the most visited theme park in Latin America with 2.5 million annual visitors.
 It was previously known as "Reino Aventura" and was a Mexican-owned and run theme park; the orca whale Keiko (featured in the movie "Free Willy") was then its principal attraction.
Six Flags Discovery Kingdom (formerly known as Six Flags Marine World, Marine World, The New Marine World Theme Park, and Marine World Africa USA) is a 135-acre (55 ha) animal theme park located in Vallejo, California, roughly halfway between San Francisco and Sacramento on Interstate 80.
 The park includes a variety of roller coasters and other amusement rides. Discovery Kingdom has been part of the Six Flags chain of amusement parks since 1999.
Roar (trademarked as ROAR) is the name of a wooden roller coaster at Six Flags America located near Upper Marlboro, Maryland.
 There were originally two roller coasters, with the first one built in 1998 at Six Flags America followed by the second one which was built in 1999 at Six Flags Discovery Kingdom.
 Both rides were designed and built by Great Coasters International (GCI).
 In 2015, Discovery Kingdom announced the retirement of Roar at its theme park, but the park later revealed that it was being renovated and transformed into The Joker with I-Box track technology from Rocky Mountain Construction.