This is an ice cave, known as "crystal Cave" on the frozen lagoon of the Svínafellsjökull glacier in Skaftafell, Iceland. This snow, which is up to 1000 years old has metamorphosed into highly pressurized glacier ice that contains almost no air bubbles.
This is not a tornado in Namibia. Where is the flying sand? This is the shadow cast by the edge of a sand dune in Namibia. The picture was entered in the Italian National Geographic photo contest by Francesco Middei.