Seventy-seven people died on that terrible Friday in July. Government investigations have found that some of the death and destruction could have been prevented with better police preparation and response-- mistakes that authorities in Chicago are now learning from.
First came the piercing bomb attack in Oslo, Norway's capital city.
"I was on vacation in Oslo with my family. . . We happened to be about 150 meters away from the blast when it went off," said Sergeant Knut Grini, Hordaland, Norway Police Department.
"I heard the blast and saw what happened on the internet so I went to work as fast as I can," said Lt. Geir Rye, Oslo Police Department.
These two Norwegian police officers have carried their experiences 4,042 miles to Illinois-- hoping that the good, the bad and the very ugly of what happened that day, will help these local law enforcement officers if it happens here.
"These are cops that are potentially going to be in the exact same situation someday," said Sgt. Grini.
It was a situation for which Norway police had very little training and preparation: the worst massacre in Norway since World War II.
After the bomb attack in Oslo, the lone wolf attacker moved to a nearby island. As police fumbled their way to the island by boat, the shooter went on a rampage through a popular youth camp and he slaughtered dozens of young people with a pistol and a hunting rifle.
"I can see a video that I've see 50 times before and I still become emotional," said Sgt. Grini.
"There are some things about this that make me emotional," said Lt. Rye.
Lt. Geir Rye, a policeman for 13 years, was on the commando team that came to the island and eventually tracked and took into custody 33-year old Anders Behring Breivik. He has since been convicted and imprisoned for both attacks.
"I had a hard time believing that a native Norwegian with the upbringing he had and no contacts with law enforcement whatsoever, I had a hard time believing he could do that altogether," said Sgt. Grini.
In a 1,500 page manifesto, Breivik's stated motive was to prevent Norway from being overrun by Muslims. In the manifesto he quoted numerous scholars from Chicago-- and claimed to have worked at Loyola University-- although there is no evidence of that. The Norwegians' visit was sponsored by Cook County's Homeland Security Department and included a day-long field exercise near Mt. Carroll, in which they ran terrorist incident response drills for local officers.
Later, at a South Side university, they staged an active shooter terror exercise showing how to conduct room by room suspect searches and communicate better.
Communication was a major problem for police during the Norway attacks: not too little information they say, but too much.
"Basically what it is breaking down a big thing into a lot of small things, making it doable. Because if you take in the whole thing it's going to be too big to manage. . .I have one person here I have to look at. Do that, move onto the next one," said Sgt. Grini.
"People sometimes say you rise to the occasion. I happen to believe you fall back to your level of training. So you want to have as many things be muscle memory as you can do," said Mike Masters, director, Cook County Homeland Security.
Both Norwegian lawmen say despite that deadly attack more than two years ago, police still lack adequate counter-terror training and some equipment. The Norwegian government this week is soliciting bids for public memorials to mark the attacks.