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Þingvellir National Park is the only UNESCO World Heritage site on the Icelandic mainland and one of the three stops on the world famous Golden Circle sightseeing route, alongside the Haukadalur Geothermal Valley (Geysir) and Gullfoss Waterfall. Just to the south of the park is Þingvallavatn, Iceland’s largest natural lake.
Geography
The first thing that visitors to the National Park notice is its sheer aesthetic beauty; dried magma fields, covered in Icelandic moss, sit carved by glacial springs and surrounded by a bowl of ancient mountain peaks.
Two of the greatest attractions in the park are the exposed North American and Eurasian tectonic plates; it is one of the only regions in the world where you can see geology such as this on land.
Visitors are encouraged to walk along the North American tectonic plate, where they can read more about the area’s fascinating formation and history, before descending into the valley below.
History

Þingvellir can be anglicised to ‘Fields of Parliament’, a nod to the area’s fascinating history and relevance to Icelandic culture. It is here, after all, that the world’s first democratically elected parliament that remains functioning, Alþingi, was formed in 930 AD.
It may seem unlikely that Vikings would want to be under such an uncombative government, but the thirty or so clans that lived in Iceland at the time sought to prosper in their harsh new environment.
The first gathering was such a success that the meetings became annual, and it became a place where disputes were settled, criminals were tried, and laws to the benefit of all were laid down.
This saw the birth of the Icelandic Commonwealth, a time of independence and freedom for the Icelandic people before they became constituents of the Norwegian monarchy. Sessions would continue to be held at Þingvellir until 1798.
Though the parliament was removed by the Danish at this time, it returned 1845 to Reykjavík.
Another major reason as to why Þingvellir is considered so important to Icelanders is the fact that this is where the decision was made to abandon the belief of Paganism and the Norse Gods; the people adopted Christianity in 1000 AD under threat of invasion from Norway.
This turning point in history was left to the pagan lawspeaker, Þorgeir Þorkelsson, who rested on the choice for one day and one night before reappearing to share his decision.
To symbolise the country’s change, he threw idols of his old deities into the northern waterfall Goðafoss, the name of which translates to ‘Waterfall of the Gods’.
Silfra Fissure
Þingvellir is one of the most widely visited attractions in Iceland, in large part due to the fact that it is home to the glacial spring, Silfra fissure, one of the top ten sites in the world for snorkellers and scuba divers.
Silfra (meaning ‘Silver’) is a submerged ravine within the park, boasting visibility of up to 100 metres (328 feet) and a temperature just above freezing. Participants in these tours will be attired at the Silfra carpark in neoprene hoodies and gloves, as well as an undersuit and drysuit for thermal protection.
シンクヴェトリル国立公園, 
Silfra is a fissure filled with fresh spring water within Þingvellir National Park, and one of the country’s most cherished wonders. Snorkelling and diving in its crystal-clear waters is an experience that is both thrilling and relaxing, and it is now considered to be one of the top five dive sites in the world. It takes around an hour to reach Silfra from Reykjavík.
Geography of Silfra

Silfra fissure opened in 1789, due to the movements of the tectonic plates that frame Þingvellir National Park. The North American and Eurasian plates, which run all the way through Iceland, separate at about 2 centimetres per year, and as they do, they tear open fissures in the land between them.
Some of the ravines fill with water travelling underground through the porous lava fields in the area, originating from Langjökull glacier about 60 kilometres north. It can take the water up to a century to reach Silfra and this long filtration process results in the water being both extremely clear and drinkable.

Because the water travels underground, it maintains a constant temperature of two to three degrees Celsius and does not freeze over immediately at the source of the spring. Snorkelling and diving tours are thus open throughout the year.
The clarity of the water is what draws most visitors. The visibility can extend to over 100 metres, allowing you to see the canyon walls and bottom like you are floating over a great cathedral.
The last colour that water absorbs is blue, which means that when you look forward in Silfra, it is as if you are looking into an ethereal, vivid, azure world. The clarity also means that sun-rays refract through the surface of the water, creating rainbows on Silfra’s bed when the weather allows.
Snorkelling in Silfra

Snorkelling in Silfra fissure is a highly enjoyable activity, but you must meet some prerequisites to be able to join. These are as follows:
- You must be able to swim
- You must be over 16
- You must be in good physical health
- You must be at least 145 centimetres and 45 kilograms
- If you are over sixty, you will need a medical waiver
- If you are over forty-five with a history of heavy alcohol use and pipe smoking, you will also need a waiver
The most common option for snorkelling is to conduct it in a drysuit. Drysuits work with a fluffy undersuit to keep your body free from water and insulated against the cold, making the task of swimming through the near-freezing temperature more than achievable.
While drysuit snorkelling is the most comfortable and popular option, a few tours allow you to go through Silfra wearing a wetsuit. Wetsuits, made of neoprene, allow water to surround your body in a thin layer, that your body then heats up and uses to protect you. Though they grant you more flexibility, they are not so warm, so this should be done by the daring; you will also need to be at least 50 kilograms to snorkel in a wetsuit.
In all tours, you wear neoprene on your head and hands to allow for better mobility, a mask and snorkel, and a pair of fins, all of which are provided on site. The course of Silfra takes approximately forty minutes, and there is a gentle current throughout, meaning it requires minimal energy to traverse.
Diving in Silfra

Diving through Silfra gives an extra dimension to its beauty, as you will be able to look up and see the sun glistening upon the surface as you cruise through the crystal clear waters. However, considering the risks associated with diving in cold water and cumbersome equipment, all who partake must meet all the requirements above, as well as one of the following:
- You must be a qualified diver with a certification in a drysuit speciality, OR
- You must be a qualified diver with at least 10 logged dives in a drysuit conducted over the past two years, signed by an instructor or divemaster.
シルフラの泉, 
Þingvallavatn (anglicised to Thingvallavatn, ‘the Lake of the Fields of Parliament’) is a rift valley lake located roughly forty-minutes drive from Iceland’s capital city, Reykjavík.
Features of Thingvallavatn
Þingvallavatn is partially within the boundaries of Þingvellir National Park, Iceland’s oldest National Park and only one with UNESCO World Heritage Site status.
Covering an area of 84 square kilometres (32 square miles), Þingvallavatn is the largest natural lake in Iceland with its greatest depth measuring at 114 metres (374 feet). Þingvallavatn is situated on the Mid-Atlantic Rift, on a part of the ridge known as the Reykjanes Ridge.
The lake has only one outflow, the river Sog.
Of particular note to biologists and fishermen are the four morphs of Arctic Char that inhabit the lake. The lake’s char are an excellent example of species evolving to fit and adapt to a secluded environment; over ten thousand years, one species of Char has transformed into four different-sub branches. Other fish in the lake include the the Brown Trout and the Three-Spine Stickleback.
History and Geology
Þingvallavatn takes its name from the historical founding of the Alþingi, which occurred in 930 AD at what is now known as Þingvellir National Park. Þingvellir literally translates to ‘Fields of Parliament’.
The Alþingi was the first democratically elected representative parliament in world history (examples such as Ancient Athens were direct, not representative, democracies); Icelanders used to travel by foot or horseback simply to congregate at Þingvellir where they would hear the latest laws and judgements of the island.
Þingvellir National Park is also notable for its geology. Given its position on the Mid Atlantic Ridge, the park is one of the only places on the planet where visitors can see both the North American and Eurasian tectonic plates standing exposed from the earth.
Footpaths allow you to get up close and personal to the plates, standing right where the ancient settlers once did. In between the tectonic plates lies fields of dried volcanic rock, blanketed with a thick, yet fragile layer of Icelandic moss.
Scuba Diving in Thingvallavatn
Scuba diving around Þingvallavatn revolves around two sites, Silfra Fissure and Davíðsgjá (David’s Crack), the former being one of the most popular spots on the planet for snorkelling and underwater exploration.
Silfra Fissure is situated between the North American and Eurasian tectonic plates and is filled with crystal-clear glacial water originating from the Langjökull ice cap. The water measures at between two degrees Celsius all year round, with a slight current preventing the fissure from ever freezing over.
Davíðsgjá is found within Þingvallavatn and is often considered the darker and more dramatic cousin of Silfra Fissure, resembling the gorge formation so prevalent across the Mid Atlantic Rift.
Only certain tour operators provide tours into Davíðsgjá, so make sure to do some research beforehand if you are looking to access this dive site during your time in Iceland.
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