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

Other days

blanket fort

Blanket Fort Day
lash

Lash Day
cat girl

Cat Girl Day
kiss a ginger

Kiss A Ginger Day
prosecco

Prosecco Day
comfy

Comfy Day
kale

Kale Day
donate your hair

Donate Your Hair Day
ruby

Ruby Day
slime

Slime Day