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Prince Charles and Princess Diana’s wedding on July 29, 1981, was considered by many as the wedding of the century. One look at her dress and you can see why. Designed by David and Elizabeth Emanuel, the dress was taffeta and lace with a 25-foot-long train.

With the 20-anniversary of her death this year, interest in the late Princess Diana is at an all-time high. TLC is airing a three-hour telecast exploring her life, legacy and conspiracy theories surrounding her death. Watch Princess Diana: Tragedy or Treason on Monday, July 31, at 8 p.m. ET.