Complex sentence: Scenia was active throughout the 1950s but was then laid on ice until it was reborn as Katterevyn in the 1980s, that today is considered a Spex and is arranged every spring.
Split into simpler sentences: Scenia was active throughout the 1950s but was then laid on ice until it was reborn as Katterevyn in the 1980s. Katterevyn is today considered a Spex and is arranged every spring.