Sarah Otto

First, we didn't have enough masks to protect us against COVID-19, then we all needed to wear them. Then we didn't, then we did again. There were fights, criminal charges and protests over them. And now most mandates are lifting.

Putting an end to the COVID-19 pandemic will mean priming the immune systems of everyone on Earth but the virus is spreading quickly and may take years to "settle down," says an infectious disease specialist.

Swallows are evolving smaller, more manoeuvrable wings to help them dodge buildings and vehicles.