Discovery Channel pushes deeper into underwater archaeology this week as Expedition Unknown heads to Greece for a high-risk dive into one of the Mediterranean’s deadliest sea passages.
Season 15, episode 4 airs Wednesday, July 9, 2025 at 9pm ET/PT, with Josh Gates joining a team of marine archaeologists to investigate a shipwreck zone long feared by sailors. Located off the Greek coast, the area has claimed at least 58 vessels and holds one of the highest densities of ancient wrecks anywhere in the world.
The episode captures Gates descending into a seabed littered with shattered amphorae, remnants of long-lost trade routes. The dive also draws on sonar and drone tech as the team maps a submerged graveyard of commerce stretching back millennia.
This latest instalment is one of the more focused episodes of the season, leaning into the historical data behind the wrecks and pairing Gates’ travelogue format with hard field research. The series has already covered Göbekli Tepe and other ancient sites this season, but the Greek segment gives extended space to maritime archaeology and the mechanics of ship loss in the region’s dangerous currents.
The episode forms part of a wider arc as the show blends historical theory with field recovery efforts. Alongside the Greek mission, the season also covers an aerial search in the Pacific for a WWII aircraft and a decoding effort in Turkey involving pre-Neolithic symbols.
Expedition Unknown continues to deliver a mix of mystery, travel, and hands-on research. Season 15 has tightened its structure around single-subject dives, with this week’s focus on the Aegean wreck zone providing a clean, self-contained entry point.
