We got used to the fact that in our world metals are solid. But there are four metals that can exist in a liquid form without any special conditions. For example, quicksilver or mercury (Hg). It is the only known metal that can stay liquid at a temperature higher than -39 °С. That is why mercury is often used in different thermometers.

The other three are gallium, cesium and francium, but they are liquid only at a temperature higher than +27-30 °С.