"Like a friend of mine says, it's a chance of a lifetime twice," Mackey told us right before she left to redo her mural on the longest remaining stretch of the Berlin Wall.

Before time and graffiti artists had their way with the 106 murals that make up the East Side Gallery, the 1.3 kilometer stretch of the Berlin Wall was a signature piece within the once-divided city.

For nearly 30 years the 87-mile-long Berlin Wall symbolized the deep divisions of the Cold War. It literally separated the families of West Berlin from the families of East Berlin. It's thought more than 100 people were killed trying to cross the wall from east to west.

On Nov. 9, 1989, tens of thousands of East Berliners crowded the checkpoints of the Berlin Wall on word that the government was ready to allow them to cross over. Unable to hold them back, East German authorities decided to immediately open the checkpoints, sending a flood of people into West Berlin.

"I saw all of that on TV, just like everyone else," said Mackey. At the time she was in London.

In the months that followed Mackey recalled thinking about heading to Germany.

"Things were happening, and I really needed to be there, so I went over on a vacation for three weeks," she said.

The East Side Gallery was born out of a desire to keep at least a portion of the Wall standing. "The premise was to get some artists together to paint on the east side of the Berlin Wall, a side which had never been painted on," she said.

Mackey, now a well-known Denver artist, was one of two Americans chosen to work on the project.

"I was really nervous because I had never painted on anything that big," she said. She called her work "Tolerance" after feeling like "there was a lot of tension with a number of foreigners in Germany." It took her four days to complete her work.

Recently Mackey received word that she would be invited to redo her mural on the timeworn stretch of the Wall. Organizers had raised 2.5 million Euros to bring back many of the original artists.

Mackey will then head back to Berlin in November to mark the 20th anniversary of the fall of the Berlin Wall. Mackey still can't believe what she saw and experienced back then.

"I actually knew somebody in West Berlin who had never been to East Berlin, and he grew up in Berlin. I actually took him over to East Berlin and showed him around his own city," she said.

"It was a phenomenal time," she added.