Staffers toured retirement homes in the United States, Japan and Europe in search of ideas.

There are rails in the hallways, and some wall corners are covered with protectors.

Different floors are marked with large images as well as numbers since some elderly people can become confused about the numbers but are more likely to remember they live on, say, the apple, than the second floor.

The northern residential buildings' stories are labeled with fruits and vegetables — watermelons, turnips and cabbages — while those in the south are labeled with animals — elephants, giraffes, goldfish.

The largest apartments feature convertible couches with backs that pull up for taller residents. Each has two rooms — in case couples sleep separately or for such cases as one couple around 60 who lives with the husband's father, who is in his 90s.

The mid-sized apartments' living rooms can be converted into bedrooms with a wall for couples who sleep apart.

Bathrooms are outfitted with rails and an emergency cord since the restroom is the place people — especially the elderly — are likely to fall.

Apartment doors are 1.1 meters wide in case residents need to be wheeled out without leaving bed.

U100's 50-square-meter apartments with a kitchen, bathroom and multifunction room cost 4,800 yuan a month, including basic electricity and water. The 90-sq-m rooms cost 5,600 yuan.