Daniel Rodríguez Bacete

Great episode. In Spain, despite the importance of Christian tradition, the day of bad luck is Tuesday the 13th. I don't know about the origin of that, but I have found that it's also in Greece, and it makes more sense because the fall of Constantinople occurred on a Tuesday 13 of 1453, but I haven't found the origins of this superstition in Spain.

Here, when someone sneezes, it is said "Jesus", supposedly to prevent Satan from entering the sneezer's mouth as is related with Alaistair explanation.

By the way, we have a very curious superstition: when you step on dog poo it's a sign of good luck, a signal of incoming money. Does this superstition exist in any of your countries)
Super interesting  Daniel Rodríguez Bacete

One of the underlying themes of the episode is really 'it's anyone's guess where the superstition originally comes from', but here's another explanation I found about the Martes 13 superstition in Spain:

The belief that Martes 13 is a day of bad luck was brought to the New World by the Spanish Conquistadors. Martes is commonly associated with disagreements because the word not only refers to the day of the week (Tuesday) but it's also the day consecrated to Mars, the Roman god of war.
Stepping on dog poo...well I guess believing that you're going to have good luck makes you feel a little bit better about stepping on it...

It's not considered good luck in the UK, but having a bird poo in you is considered good luck by some people (see here). Although my personal experience suggests it isn't particularly lucky at all...
Hi mates. This is Daniel from València in Spain. I'm glad for this brand new forum platform, it's an amazing way for slight thighs with the Leonardo community.

Thanks for your hard work Alastair. This was a fantastic idea. I hope that we can take profit of it in our English learning road.