Metro almost empty on Fridays

I have written already a bit about the Madrid metro and how I like its smell, its efficiency in getting you from A to B really quickly. 

There is one thing about the Madrid metro you should know. On Fridays during the day it is almost empty. I am not sure why. My theory: most Madrilenos are already in weekend mode and skip the working Friday. I will watch the phenomenon closely, but now after months and a long statistical serie I can confirm that Fridays is non-metro day and the crowdiness is significantly lower than on other days.

By the way, the photos shows the Atocha Metro station and railway station where palm trees are growing inside and turtles having a great time.

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