How was settlement similar in St. Petersburg, Russia, and Manaus, Brazil?

Both cities required substantial changes to their land to support settlement. St. Petersburg was built on marshy, low-lying land, which had to be drained and altered; Manaus developed in the Amazon region, where land and waterways also had to be adapted for urban growth. The similarity is major land modification, not shared climate, mineral deposits, or naturally flood-resistant hills.

AI-written and checked against the verified answer.