Weeks in Estonia start with Monday (which is called "first day" -esmaspäev- in Estonian). Next three days also contain corresponding numbers in their names, while Friday, Saturday and Sunday do not follow similar logic.

I think it's better the way it is now, so we don't have to discuss which is the first day of the week.
In Spain, and Catalonia, the weekend is formed by Saturday and Sunday

In catalan, the first day is Monday.
And the names come from latin.
(English - catalan --; latin)

Monday - Dilluns --; Dies Lunis.
(Day of the moon)
Tuesday - Dimarts --; Dies Martis.
(Day of Mars)
Wednesday - Dimecres --; Dies Mercuriis.
(Day of Mercury)
Thursday - Dijous --; Dies Iovis.
(Day of Jove, Jupiter)
Fryday - Divendres --; Dies Veneris
(Day of Venus)
Saturday - Dissabte --; Dies Sabat.
(Day of Sabbat)
Sunday - Diumenge --; Dies Dominici.
(Day of The Lord)

see ya!