Waking up from the overnight train in Country #15 — Sweden, we arrived in Malmö to the sound of light rain and the sight of pastel-colored buildings shimmering in the puddles. After a Scandinavian breakfast of dark bread, salmon, and coffee strong enough to wake a Viking, we explored the compact old town before boarding the train across the Øresund Bridge — one of the world’s great engineering achievements.

Opened in 2000, the 16-kilometer Øresund Bridge links Sweden and Denmark, symbolizing European cooperation and connection. Crossing it by train was surreal — first traveling over water, then diving into a tunnel under the strait before emerging in Copenhagen, our 16th European country.

In the afternoon, we visited Den Blå Planet (The Blue Planet), Northern Europe’s largest aquarium. Its swirling architecture resembles a giant whirlpool, and inside, we explored coral reefs, Arctic seas, and a rainforest zone. During our behind-the-scenes tour, we learned how the staff maintain the massive ocean tank and care for its creatures.

The aquarium sits near the Øresund coast, not far from where American and NATO naval vessels sometimes operate during joint Baltic exercises — a reminder of Denmark’s ongoing partnership with the United States in regional security.

Øresund Bridge is just under 10 miles and an engineering feat connecting Denmark and Sweden. Denmark is currently working on another challenge to connect Denmark and Germany through an underwater tunnel stretching 11 miles.