In shock and grief, South Koreans are mourning the losses of innocent young lives at Saturday night’s deadly crowd surge in Itaewon. At least 154 people -- most of them in their 20s -- died in the country’s worst disaster in years.

The narrow alleyway where the fatal stampede took place is still blocked for police investigation. But not far from the disaster site, flowers, messages and beverages have been laid out on the ground in memory of the deceased.

Mourning altars have been set up in Itaewon and elsewhere across the country, where politicians, celebrities and pedestrians have been trickling by since Monday morning.

Following are some photos from a nation grieving and in mourning on Monday.