They may be either large pillar candles like those you get in a church, or the classic dinner taper, for which you will need an elegant candle stick. These tend to suit classic dining rooms and old country inns. They are fantastically atmospheric and work really well if you have large tables and plenty of space. Be careful when buying these sorts of candles, that you are buying a good quality candle. Generally, you are better off paying more for a good candle than trying to get the cheapest.
Many Chinese manufactured candles, particularly some of those that you buy cheaply in supermarkets, are made of whipped wax, which means that the centre of the candle, hidden inside a smooth, solid outer wax wall, is like whipped egg white. This means that the centre burns away very quickly, and in next to no time you have an ugly, large smoky flame that is almost invisible inside a wax pillar, until the whole thing collapses. You can tell a whipped wax candle from a solid candle by comparing the weight of each one in your hand. The whipped one will be much lighter.
Test the manufacturers claimed burning time. If a 120 hour burn time is stated on the candle, but after 60 hours it looks rubbish, the candle flame has disappeared inside the candle or it has simply turned to mush, then you only get half the claimed value.
There can be an issue with mess when using pillar candles. You will need some sort of base, and depending on the quality of the candle this may still not be enough to prevent the cascade of molten wax that can fall from the caldera. This can look very atmospheric and attractive, but also, if you do get wax on table tops or linen, it can be a real problem to clean off