When I write a book, I always try to visit the country I am writing about.
I don't have the confidence - or arrogance - as a writer to write about a place I have not been to.
I also read books about the places, look on YouTube at footage for settings and characters, as well as talking to people from the countries I choose.
But nothing beats going there.
Poland is one of the places where Euro 2012 is being played. That's why I chose it.
The story of Black Op is that a terror group is planning to attack England's football team as they prepare for Euro 2012 in Krakow.
So I went to Krakow.
First I read the Rough Guide. Then I headed off to Poland.
This is a beautiful palace on top of the hill alongside the river on the outskirts of the city centre in Krakow. When I was sat there I recognised that it would be a great place - possibly the only place - for a helicopter to land in the middle of the night, without ruffling too many feathers.
So I put that in the story.
This church - on the left - is fascinating. The taller tower plays host to a trumpeter, who, as regularly as clockwork, plays his trumpet to mark a significant moment in the history of the city.
This is described in a small book of stories about the city that I bought in the tourist information shop in Krakow.
The noise echoes across the squares and narrow roads of Krakow, even during the night.
When I heard the trumpeter I understood how the spy characters in Black Op would be able to identity and try to stop a crazed former-KGB agent from attacking the England team with a rocket launcher.
Even if I am not writing a book, I love to travel to places. I like to read the stories about how the city came to be, including the myths and legends that define a place.
I like reading travel writing for that reason too.
In fact, I wish I could be a travel writer.
But I'd rather be a good husband and father and I don't think I could do both well. Yet.