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Archaeologists excavating an industrial estate… found a megalithic complex.
Neolithic seafaring
Discovered as recently as 1989, the Neolithic settlement submerged beneath the waters of Lake Bracciano, at La Marmotta, near Rome, Italy, has yielded rich evidence of life 7,000 years ago. New analysis of the five boats found at the site suggest that they could have been used for the sea voyages that led to the spread of Neolithic practices to the islands of the Mediterranean.
A paper in the journal PLOS One (https://doi.org/10.1371/journal.pone.0299765) says that earlier boats dating back 10,000 years have been found in European waterways, but all were designed for use on rivers and lakes. The five hollowed-out tree trunks excavated from La Marmotta are substantially larger than earlier boats and one has four transverse ribs designed to provide additional strength and improve its handling.
The same boat has three wooden T-shaped plates, pierced with rows of holes, inserted into its starboard side. These could have been used to fasten ropes tied to a possible sail or to join other elements such as a stabiliser or even another boat to create a double-hulled catamaran.
Bracciano is 9.3km across today and was smaller still in the Neolithic. Its scale would not have required boats of 11m in length for transporting people, animals, or goods. The lake is connected to the Mediterranean by the Arrone river, over a distance of 38km, and it is possible that the boats were used to travel via the river to the sea and beyond.
Obsidian from the islands of Palmarola (some 40km offshore) and Lipari (located off the north coast of Sicily) was used to make tools at La Marmotta, and ceramic finds from the settlement demonstrate that it was in contact with Greek and Albanian communities. It is very likely, the authors conclude, that many major advances in sailing were made in the early Neolithic as a result of social organisation that encouraged specialisation and dedication to particular tasks.
Rice as evidence of long ocean voyages
Further recent evidence of journeys by sea comes from the thin sectioning of red-slipped pottery, known as Marianas Red, excavated from the Ritidian Site Complex on the Western Pacific island of Guam. The pottery has been found to contain the remnants of rice husks and leaves, representing the earliest evidence of rice cultivation in Remote Oceania and for the longest known ocean voyage of the time across 2,300km of open sea.
Rice phytoliths – the microscopic silica structures left behind by plant cells – have been used to date the pottery to c.1500 BC. Previous archaeological evidence for rice in Remote Oceania dates back only 1,000 years.
In a report published in Science Advances (https://doi.org/10.1126/sciadv.adw3591), the authors state that rice was already a staple crop in the ancestral Austronesian regions of Taiwan and the Philippines, but was unknown in any of the Pacific islands at the time of the first European encounters in the 16th century, with the exception of Guam and the adjacent Mariana Islands. However, its use here was probably restricted to special ritual events, because there is no evidence on the island for ancient rice fields, irrigation systems, or harvesting tools.
One of the report’s authors, Dr Hsiao-chun Hung of the Australian National University, Canberra, said: ‘rice was a cultural symbol carried across great distances, likely used for ritual purposes rather than daily consumption. It underscores how deeply intertwined food, migration, and identity were for these early voyagers.’
Heavy transport
Our prehistoric ancestors were also capable of transporting large blocks of stone by boat or raft some 5,300 years ago, according to a paper in the Journal of Archaeological Science (https://doi.org/10.1016/j.jas.2025.106263).
The report concerns a substantial piece of gypsiferous cataclasite known as the Matarrubilla stone. Shaped into a square basin, the stone forms the centrepiece of the circular tholos at Matarrubilla, a Copper Age megalithic burial mound located at Valencina, in the province of Seville, southern Spain.
Measuring 1.7m by 1.2m and weighing 2 tonnes, the stone is notable for its special visual qualities. Within the gypsum matrix, there are bands of green, red, and white (represented by inclusions of variscite, jadeite, slate, red conglomerates, cinnabar, iron pigments, quartz, and limestone). The multicoloured nature of the rock must have made it symbolically and aesthetically appealing: previous studies have revealed the importance of colour in megalithic architecture across Europe.
The nearest source of gypsiferous cataclasite is at Finca el Concejo, near Las Cabezas de San Juan, approximately 55km from Valencina, while another potential outcrop is located in the area around Coripe, 72km away in a straight line from Valencina. Both are on the opposite side of the Guadalquivir river from Valencina, implying that some kind of boat or raft was used to transport the basin across the wide river estuary to the western shore. From here, it was probably dragged 3km uphill to its final location in Valencina (140m above sea level at the northern end of El Aljarafe plateau), using a sledge pulled by people and/or oxen.
This form of water transport aligns Valencina with other major prehistoric ceremonial sites such as Newgrange, in Ireland, where the colossal kerbstones are believed to have been quarried at Clogherhead, 25km away, and transported by boats along the coast and up the River Boyne, and Carnac, in Brittany, to which megalithic stones were transported over distances of up to 40km.
The authors conclude that the Matarrubilla basin might have served as an altar or offering table, and that it represents the initial stage of the development of the site as a place of congregation and ritual importance for the communities living across what today is the lower Guadalquivir valley. This then developed into a major focus of social and ritual life in 3rd millennium BC with the construction of the architecturally impressive tholos, whose chamber (2.75m in diameter) is approached by a 33.46m corridor, aligned towards Arcturus, one of the brightest stars visible locally at the time.
As well as the basin, the tholos contained large quantities of non-local and exotic materials, including 100 ivory objects, gold foil fragments, flint tools, a serpentinite axe, ceramic pots, variscite beads, rock crystal, ostrich eggshell, amber, and cinnabar.
Dating the Carnac megaliths
Archaeologists excavating the site of an industrial estate at Le Plasker, in Plouharnel, Brittany, have discovered a hitherto unknown megalithic complex from which accurate dates have been obtained for the first time in the long history of research at Carnac. In a report published in Antiquity (https://doi.org/10.15184/aqy.2025.10123), the authors claim the site to be one of the oldest of its kind in Europe.
Though the actual stones from Le Plasker do not survive, the authors of the study found the foundation pits for multiple standing stones, as well as cooking pits, a stone cist covered by a mound, and an oval ditch, which is interpreted as the perimeter of a Mesolithic hut, briefly occupied between 5681 and 5621 cal BC.
Around 4700 cal BC, a cist was erected on top of the hut and buried under a circular mound, measuring 3.3m in diameter. The dimensions of the cist (0.7m × 0.9m) suggest that it was originally intended for a single individual buried with the lower limbs strongly flexed, but no bones or grave deposits were found.
Over a 300-year period between 4600 and 4300 cal BC, the standing stones were erected in three alignments. All three phases followed the same north–north-west to south–south-east alignment as the cist, each respecting its predecessor, and thus ‘demonstrating a persistence in societal traditions and symbolism’. The associated hearths were probably used for cooking and feasting, but they would also have illuminated the stones.
Packing stones in the pits suggest that the standing stones, of about 3m in height, were brought to the site from granite outcrops a few kilometres away, the overall effect being to create a resemblance to the original rocky landscape from which they had been sourced.
The megalithic complex at Carnac was designated a World Heritage Site at the 47th session of the UNESCO World Heritage Committee held in Paris in July 2025. According to UNESCO, its universal value derives from the fact that its purpose is not fully understood: ‘this ambiguity sparks curiosity and encourages ongoing research and interpretation, highlighting the enduring fascination with the past’, the inscription statement concludes.
Chris Catling is an archaeologist and writer, fascinated by the off-beat and the eccentric in the heritage world.
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