Āraiši lake castle located in the settlement Arashi, 7 km South from Cesis. The castle is a reconstruction drevnekitaiskogo water castle. The buildings of the ancient Latgalians 9th century has been reconstructed, based on the remains of wooden structures and various ancient objects discovered during archaeological excavations.

Place Arashi is one of the few in the country, where they found the remains of a mammoth. Lake Arashi in the distant past was much larger. Currently, the area is about 30 hectares, maximum depth is 11 meters. In the lake district in ancient times was the natural emergence of the so-called "lake of castles". Igraszki castle is the first and most extensively studied among the castles of this type, and because the idea of the renovations and the opening of the Museum under the open sky.

Visitors Āraiši lake castle often wonder why this bunch of wooden buildings called the castle. If the summer water barrier can be considered a kind of protection from invasion, in the winter, when the water in the lake freezes over, these wooden houses from attack, nothing could protect. However, in ancient times, the climate in the area where today is the castle that was slightly warmer and in winter the lake if and froze, just for a little while. So in winter time the lake was also a protection for the settlements. So archaeologists call these constructions lock.

Interest in the ruins of Āraiši castle appeared in 1876, then Assisi Earl K.-G. Sievers opened the castle as a monument, believing that this is the remains of a stone age raft. Later cited different hypotheses about the origin of these buildings and figuring out what they were actually. However, excavations to confirm one or another hypothesis, nobody carried out.

In the period from 1959 to 1964, during a survey of underwater archaeological sites in Latvia lakes region were found the remains of another 9 villages. Similar to those that were found on Erisscon the lake. It became clear then that could open a new category of archaeological sites. To carry out an extensive research chose Āraiši lake castle. The research was conducted from 1965 to 1979 under the leadership of J. Apalsa.

As a result of excavations, it became clear that the lake settlement was established in the 9th-VV lived it the largest of the ancient Latvian tribes community of Latgalian. The Foundation of the dwellings have been preserved almost completely, partially preserved remains of wooden buildings. For the study of the castle of scientists sank to the bottom with scuba diving. Remains of buildings was covered with thick layer of silt. They found not only the wood but also various Antiques: pottery, vessels, etc.

For the entire period archaeological site was found about 150 buildings. The castle itself was a complex of buildings located on a rectangular wooden flooring. The castle consisted of 5 rows of smoky huts and outbuildings, which were located on the perimeter of the site in 4 rows. Between dwellings was held streets, width of one and a half to three and a half meters. Around the castle were lined with timbered walls, which protected him. With coast lock connected the bulk dam. It is assumed that the castle was inhabited by different sectors of society, evidenced by the discovery of ancient objects, and found lodgings that vary in size and volume.

What remains of the castle were under water, is explained very easily. Before the water level in the lakes was significantly lower than in our days. However, in the 10th century, in the Northern hemisphere of the Earth entered a period of high humidity with frequent rains. As a result, the water level in the lakes quickly rose. Water mothballed buildings, and thus remains preserved to our days. Museum Āraiši lake castle was founded in 1983. Today there are numerous festivals and events.