Welcome to the documentary podcast from the BBC World Service.
This is assignment.
I'm walking through the town centre of a city in western Ukraine.
The sky is blue,
the roads are full of traffic and there is a buzz on the streets as locals go shopping.
This region has not been targeted and it certainly doesn't look like a war zone.
I'm with a young man who is signing up to the Ukrainian Armed Forces today to join the fight against Russia.
He's sorting out the relevant paperwork.
But this future soldier is not Ukrainian.
He's from Colombia.
This is Guardian.
He's 28 years old.
Guardian is his military call sign.
And throughout this program, that's how I will refer to the soldiers I meet.
Guardian had previously been a soldier in Colombia.
After paying for his own flights to travel halfway across the world,
he's now committed to defending Ukraine.
As he walks to the bank in his camouflage trousers, Ukrainian passers-by cannot help but notice.
He's greeted as a war hero by a group of kids.
They look about 12 or 13 years old, a mix of boys and girls.