Airport Shuttle

If you were a youngster in the 1990s (and a geek), you may recall Mattel's "Classic Town" collection, which included this hyper-realistic Airport Shuttle. What's the big deal? Because it was one of the few monorail sets with a looped track and a train that ran on batteries.

This Airport Shuttle 730-piece model, which originally retailed for $140, sits alongside other monorail models such as the Futuron Monorail Transport System (1987, set #6990) and the Monorail Transport Base (1994, set #6991), which trade for over $1,000 on collector markets. "The monorail is in high demand since it was produced in limited quantities," adds van IJken. "In reality, according to legend, Lego outsourced the manufacturing of the monorail tracks — just the rails, not the trains — to a bankrupt firm. As a result, the track tooling components were lost, and the monorail sets were abandoned."

Cost: $2,484