Here in Iceland during this shortest daylight time of year the sun sets and rises equally slowly as it does during the longest daylight of the year in June, just in the opposite direction. In January the sunset/rise can be seen to the south but to the north in June/July.
These two times of year offer the best low angle light in Iceland as the low angle light last for hours. Other times of the year the sun sets and rises much quicker.
Lake Þingvellir is formed where a depression and cracks in the ground from the rift between two tectonic plates reveal underground water. On the northern part of the lake fresh filtered water flows from underground into the lake. This underground water is exceptionally clear. Diving in popular in the underground fissures and ravines where visibility can be over 100 meters. This underground water has a very consistent temperature during the year and where it flows to the surface, patches of unfrozen water can be seen.