Big-dreaming Dallas has long been embarrassed by its little Trinity River, and so city boosters have sought to transform it. They failed to navigate it in the 19th century. They straightened it to control flooding in the 20th. And in the last few decades, they have dreamed of turning it into a grand urban park. Plans for a multi-lane toll road running through the Trinity’s floodplain have dogged the park project. But two Santiago Calatrava-designed bridges have been built. They’re an ironic reminder that, in spite of the city’s attempts to dress up the Trinity, it remains wild and temperamental, swelling during annual floods and attracting birds traveling one of North America’s great avian migratory highways.