These formations, known rather poetically as “murmurations,” are so large they can block what remains of the daylight as the birds decide where to roost for the evening. Just after sunset, the starlings, which come to the marshes to feed on insects and larvae, rise en masse into the purple-streaked sky. This event is known in Danish as the sort sol (black sun), and it’s an awesome sight to behold. In Denmark's vast Tondermarsken marshland, twice-annual starling migrations literally turn the sky black. Take a guided night walk to see the bubbles in starlight. “Along the way, bacteria can act on it and produce methane products.” The gasses that are caught mid-rise as the lake begins to freeze are then trapped for the winter, he explains. “When organic matter falls into the lake it can actually sink down to the bottom,” he says. The bubbles are created by organic matter like bits of plants that fall into the lake, explains Amos Tai, an associate professor in the Earth System Science Programme at the Chinese University of Hong Kong. An artificial lake on the North Saskatchewan River, Lake Abraham has milky blue water due to the presence of tiny rock particles, which makes a stunning backdrop to the bubbles.
In winter, frozen methane bubbles give this lake in northern Canada a psychedelic dotted appearance, drawing photographers from far and wide. Frozen bubble lake, Lake Abraham, Alberta, Canada From a never-ending lightning storm to a glowing canyon, these are sights that showcase the wonder-and strangeness-of our natural world. Vacations may still be more aspirational than realistic for most of us, but as the world begins to open up again, here are nine mind-boggling natural phenomena worth traveling for.