Interest in the first world war, wrongly thought to be unforgettable, waned as its veterans died.

ECONOMIST: Britain celebrates a piece of history that is rapidly dying

This is my first time, so I'm excited about giving -- and having -- an experience that will be unforgettable.

CNN: R. Kelly ignites Day 2 of Coachella

Viewing the vast tranches of rock from the air on a helicopter ride or from the transparent Skywalk will be an unforgettable experience for any child.

BBC: Five family-friendly adventures

Turned out to be an unforgettable weekend.

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The price to travel across the diverse Alaskan landscape by bush plane can be expensive during the Iditarod, but the experience is almost always described as unforgettable.

CNN: Iditarod: A spectator's guide

Maybe -- if we're being picky -- this is all too self-consciously clever to be truly scary on the visceral, soul-gnawing level of the most unforgettable horror films.

CNN: Review: 'Cabin in the Woods' is sheer horror heaven