working in Varberg, , have made the incredible discovery of six historical shipwrecks. The wrecks were unearthed during investigations in advance of the Varbergstunneln project.

According to a report by , the six shipwrecks were discovered near Varberg's original shoreline in southwest Sweden. The ages vary widely, from the Middle Ages to the 17th century. They all display a fascinating range of historical boatbuilding techniques in Europe.

Varbergsvraken 2 is a clinker-built sailing ship that was constructed during the 1530s using locally sourced oak timbers. These types of vessels has overlapping planks, which gave the vessels a rigid or stepped appearance along the hull - one of the oldest boatbuilding techniques in northern .

One key feature of this wreck is the remains of a berghult - a reinforcing strip on the hull that protected the ship during docking. Traces of burning on this strip suggest that it may have been damaged, or intentionally set on fire, before the .

Varbergsvraken 5, also a clinker-built ship, dates from the 17th century, during which time Sweden became a great power in Europe and exercised territorial control over much of the Baltic region. During this period, known as the Great Power era, it also held territories on the and some overseas colonies, including New Sweden in the US.

Like Varbergsvraken 2, it was also built from locally sourced timber and likely sailed between the medieval towns of Varberg and Ny Varberg, a city just over three miles from present-day Varberg, which was founded in the mid-15th century and abandoned around 1612.

Varbergsvraken 6 is a carvel-built ship - planks joined edge to edge - and shows some influence from shipbuilding techniques. This wreck is the only example found during the excavations that has a preserved keel, the backbone of a ship.

The team is now preparing an analysis of Varbergsvraken 3 and 4, two 14th century cogs, which may shed light on medieval maritime trade.

The archaeological works were carried out by the Bohuslan Museum, Visual Archaeology and Cultural Environment Halland.