Oops, it doesn't look like 'metro day' is a national day..

Other days

artists

Artists Day
tulip

Tulip Day
nae nae

Nae Nae Day
cursing

Cursing Day
boba

Boba Day
no bra

No Bra Day
chocolate milkshake

Chocolate Milkshake Day
stud

Stud Day
prosecco

Prosecco Day
my little pony

My Little Pony Day