It’s the only place like it on earth: A bridge between two worlds… The Isthmus of Panama. For millions of years, it has provided a critical throughway and vital rest stop for millions of birds, mammals and reptiles moving between North and South America. But now, it’s changing, almost in front of our eyes. Environmental challenges could act to shut down this unique linkage, with serious consequences. We follow Smithsonian-funded researchers and other scientists as they use cutting edge tracking technologies to explore these threats, and gather the evidence we need to confront this challenge, before it’s too late.