The island of Hong Kong is filled with many large and steep hills. This causes a lot of issues with city planning, and the issues with city planning have led to traffic concerns. To alleviate traffic in the Mid-Level (a residential area in Hong Kong) the Central–Mid-levels escalators were built. It has become the longest covered escalator system in the entire world.
It takes 20 minutes to ride the 800 meters of 20 escalators and 3 moving sidewalks. Although the original goal of reducing traffic was never realized, new restaurants and shops have opened on the Upper Level due to the daily traffic reaching about 55,000 people. This is much beyond the original forecast of 27,000 people per day.
Photos by zh FongCYu, K.C. Tang, and Maucaine respectively