If you start on the surface of the Sun and travel outward on a beam of light, it would take you, on average, about three minutes and twelve seconds to reach the planet Mercury. There, at a distance of almost 58 million kilometers, you would be as close to the Sun as it's possible to get while still having something stable to stand on.

Due to this relative proximity to its star, Mercury has a short orbit, and finishes one revolution around the Sun in only 88 days. To an observer on Earth, Mercury would appear to move faster across the sky than any other visible planet, and this is how it got its name. Mercury after Mercurius, the Roman god of commerce, travel and thievery, counterpart of the Greek god Hermes, fleet-footed messenger of the gods.

Being a terrestrial planet, Mercury has a geological composition analogous to that of Earth. An iron core with a silicate outer shell, making for a rather high density, second only to that of our own planet.

As a kid, I daydreamed about going to Mercury. I'd read about how close it was to the Sun, and I thought that from there, our great star must really be a sight to remember. Gigantic and flaming, lighting up the entire sky in a way no earthbound observer would know. To see the Sun not just as a light in the sky, but as the great, massive sphere of fire it is. Surely it must be a marvel to behold.

Once there however, things could quickly get rough. Mercury is like a terrestrial desert, but many times worse. A Mercurian day lasts for 59 Earth-days, and during this time The Sun will make temperatures climb to about 700K, only to have them drop to 90K during the night. This gives Mercury the most extreme temperature variations in the solar system. Venus is slightly hotter, but in return, much more stable.
Bad as this may seem, though, it ought to theoretically allow for a window, at dawn, say, where the temperature is a mild 300K (~25°C, like a Swedish summer), and when it would be possible, if only during hours, to walk the surface of Mercury with nothing but a tank of oxygen and a radiation suit. You'd skip lightly among the rocks, and see our closest star, intense and blazing, ever so slowly crawl up over the horizon.