By Matthew Price
BBC News, De Kalb
The sun is bright at Northern Illinois University - so bright you have to screw up your eyes against its reflection off the snow.
It is also bitterly cold. Too cold to hang around outside for long. But all day people did that.
They came, and stood, and cried, and prayed outside the building where five students were killed by a lone gunman.
Two students stood, clutching one another, and both made a short prayer out loud. They had known one of those who was killed.
In front of them, on top of a small mound covered in snow, someone had placed five white crosses with the names of the dead painted on in red.
A mother, father, and daughter walked slowly up the slope, put down some flowers and stood silently for a moment. Then, the mother gently brushing her daughter's face with her hand, they walked off with their arms around one another.
Around the corner is the building itself where a 27-year-old former student here had strode in during a geology lecture and opened fire.
Imagine seeing that. A man dressed all in black. He brings his gun up and fires at your teacher. You see him swing towards the lecture theatre, and realise he is about to fire again.
All you hear, if your brain does not shut out these details, is the sound of the bullets being fired - about 50 of them we are told.
The gunman was named as former student Stephen Kazmierczak
You hear screams. Perhaps smell the gunpowder. See the blood. You would never be able to forget these seconds of horror.
And thousands of others on campus will also never truly forget. I spoke to some students as they wandered through the university.
Within minutes of the attack they said text messages and emails were warning them to stay indoors. They were put under lockdown.
Alex Hari told me he had tried to ring his parents, but so many people were trying to use the mobile network that the phones stopped working.
He said he was feeling better today, but I felt he still had a lot to get through.
It is hard to say how a university gets through something like this.
Today, in the snow and the cold, it is clear people are managing in their own quiet way. Many individuals here will get through it.
But Northern Illinois University will forever now be associated with the day when a lone man carrying his weapons in a guitar case inexplicably decided to end so many lives.