Aeons before Hong Kong and Shenzhen became bustling metropolises separated by a border and checkpoints, the stretches of land where they would eventually arise were simply part of the same volcanic area in southeastern China. Fast forward to today, and that shared ancient history has become the architectural inspiration for the revamped Huanggang Port. Nestled amid skyscrapers, the 60-by-200-metre checkpoint sits at the limits of Shenzhen’s Futian district and resembles a giant cornerstone. The...