Denmark, particularly in Copenhagen, has installed floating platforms/islands planted with wildflowers and native vegetation in its harbors and canals. These create safe urban habitats and sanctuaries for birds, bees, pollinators, insects, and even some aquatic life.
The Wild Mile: Floating Wetlands Restore Diverse Wildlife to the Chicago River — Healthy Lakes

Deep in the heart of urban Chicago, a network of floating wetlands is restoring native wildlife habitats, increasing biodiversity, and encouraging recreation along the north branch of the Chicago River. Known as The Wild Mile, the interconnected islands were installed by grassroots environmental res

Healthy Lakes