Most metropolis' are so busy building the future that they don't have time to re-think the past. Not so with Seoul, South Korea. In 2003, the city demolished a downtown freeway to restore an ancient stream that once flowed beneath the thoroughfare. More than 75% of the scrap material from the demolition was re-used to reconstruct and rehabilitate the stream banks and create a commercial corridor. In this episode of e2, we'll see how the Cheonggyecheon is now a thriving tourist destination, proving that going backward can sometimes lead to an even bigger step forward.