Using satellite-based LiDAR mapping, researchers have discovered a vast network of artificial islands and stone-lined canals hidden beneath the dense vegetation and silt of the Bengal Delta. Known as "The Emerald Atolls," this urban sprawl dates back to the 5th century CE and suggests a sophisticated culture that thrived in a fluctuating aquatic environment.
The discovery challenges existing models of urbanization in South Asia, revealing that the delta's inhabitants constructed massive stilt-platforms and stone embankments to protect against seasonal flooding. The site also yielded evidence of an advanced salt-refining industry and maritime docks, suggesting that this lost metropolis was a primary gateway for trade across the Bay of Bengal during the Gupta and post-Gupta eras.