There are all sorts of myths and rumours about the differences in the way the world works on the two sides of the equator, with some people claiming that water drains clockwise in the northern hemisphere and anti-clockwise in the southern hemisphere. However, while this particular quirk has never been proven (as the direction in which water drains is actually influenced by a range of factors), there are a number of very real differences which are worth looking out for when crossing the equator.
The most notable and spectacular of these can be experienced at night. For example, as the southern hemisphere faces towards the centre of the galaxy and the northern hemisphere faces away from it, the countries to the south of the equator tend to be much better for stargazing, with the Milky Way being considerably more visible in the southern half of the world. What's more, those with an interest in astronomy and astrology will notice that the constellations on view tend to differ depending on where on earth you are. The Southern Cross, for instance, can only be seen in the southern hemisphere, and is often of particular interest to avid stargazers who are visiting from the north.
Another thing which should not be forgotten when crossing the equator is that the seasons will be the other way round, so if it's winter in the UK, for example, it will be summer in Australia. It's important to remember this when booking holidays, as you certainly won't want to turn up somewhere in the middle of winter when you were expecting sunshine.
Speaking of sunshine, it's interesting to bear in mind that when the sun is at its highest point - which occurs at midday - it will be to your south if you're in the northern hemisphere and to your north if you're in the southern hemisphere. This is something that is rarely going to make any difference to you, although if you happen to be lost in the desert without a map or a compass, knowing this little piece of trivia could save your life!