We began crossing one of the wonders of the modern world last night when we entered the Gatun Locks and began the first half of our transit. Three sets of locks led us directly onto a manmade lake 85 feet above sea level. Early in the morning, those of us up early could hear howler monkeys calling from the island in front of us. These calls are a hallmark of neotropical rainforests.

We prepared for our first outing of the week by gearing up with binoculars, water bottles, cameras, and sunscreen. We left National Geographic Quest for a boat/bus/walking adventure at the Rainforest Discovery Center (RFDC). Established in January 2008 by then President Martin Torrijos, the RFDC is located on the famous Pipeline Road. The site is world-renowned for birdwatching. In 1985, 385 species were identified in two hours, a record number for bird counting.

The visitor’s center and observation tower, the work of architect Patrick Dillon, make the least possible impact on their respective sites. In their own ways, each reflects sustainable design principles, including the use of recycled building materials (structural steel, wood paneling, and flooring), the collection, treatment, and consumption of rainwater, the treatment and recycling of sewage and other effluents, and the integration of natural ventilation systems.

We transferred from our Zodiacs to local fiberglass outboard engine boats. We admired the beauty of the rainforest as it draped over the light-reflecting waters of Gatun Lake. As we cruised, we spotted wildlife in the lake’s floating vegetation and in the small islets inside the lake. The most amazing spotting was a giant vessel as it emerged from the forest-covered edges of the island.

Back on the ship for a well-deserved lunch, we spent the rest of our day transiting the Pacific Ocean for the second half of our Panama Canal transit. We crossed the Culebra Cut, Pedro Miguel, and Miraflores locks. We then exited our crossing of the Isthmus of Panama under an iconic and classic bridge, the Bridge of the Americas. This marked the continuation of our week’s adventure in Panama and Costa Rica.