Iceland has created many places that are not like the earth because of its unique geographical environment, and the Blue Ice Cave is one of them. The blue ice cave is a natural ice cave formed under the Vatna Glacier environment. Due to the movement of the glacier, its location changes every year, so its shape also changes subtly. In addition, with the different time of day and different light, the blue ice cave will look different.

The natural blue ice cave is Iceland's national treasure, which is rarer than the aurora. The ice cave is actually frozen water, but when it is frozen, the water still maintains a flowing shape, so the ice you see in the blue ice cave is sparkling and very fluid.

Glaciers are "big players" in making ice caves, and the Vatnajökull glacier in Iceland is naturally unequivocal. Ice caves are formed because some of the ice in the glacier is thinner. Especially in places where heat is concentrated, a volcanic geothermal place will melt a hole from the inside. Or in a place with direct sunlight, a skylight will be opened when the ice above melts away. Ice caves look very different in different weathers, even at different times of the day in the same weather.

Standing in the ice cave is like diving under the sea. Looking up at the sun through the water, the eyes are full of hazy but very deep blue. The ice layer froze instantly like a huge ocean wave. Some layers of ice that are free of impurities appear clear and translucent, and thicker layers of ice appear blue-green; some are covered in volcanic ash and appear bright black. If you stand at the entrance of the cave, the change of external light makes the color of the ice cave look diverse, the whole world will be ignited by the sun, and there will be an illusion of warmth.

But due to gravity and the movement of the glacier, the ice layer will slowly move downward, about a few centimeters per day, so in just a few weeks, the ice cave will be filled with ice, and it will naturally seal and disappear forever. Then there will be new ice caves in new places where the heat gathers, and you can't step on the same river, and you can't see the same ice cave.

In Iceland's Vatnajökull glacier, visitors are only allowed to enter from November to March of the following year, and a maximum of 200 tourists are received during this period.

When it comes to the opening time, we have to mention the reason for the formation of the blue ice cave - the blue ice cave is actually formed by the melting water of the glaciers in summer. The flow of water continuously cuts the bottom of the glacier, forming underground passages one by one.

In winter, the temperature drops and the meltwater freezes, forming these large and small ice caves. Therefore, only in winter, the structure of the ice cave is stable enough to ensure that everyone can enter the tour safely.

Due to global warming, the size of glaciers is also shrinking year by year. Therefore, in some years, if the temperature is not low enough, it may be impossible to safely enter the blue ice cave due to the accumulation of water in the cave or the instability of the ice layer at a relatively critical time such as the beginning of November or the end of March.

Although there are many problems at these critical times, it does not mean that the ice cave can be entered at other times. If the weather is bad and the blue ice cave is unstable, it is also inaccessible. Therefore, we can visit the blue ice cave only on the premise that the blue ice cave is stable and safe.

To some extent, the blue ice cave is just like the aurora, which can be met but not sought after. Although it will form in winter, it may not meet our psychological expectations for various reasons. There's no way to be absolutely sure when the best time to visit is, and exploring the Blue Ice Cave does require a bit of luck. It is precisely because of this that the Blue Ice Cave is so charming.