One day, one of a pair of identical twins celebrated their first birthday.
Two days later, the other twin celebrated their birthday.
The twins were born within 5 minutes of each other - so how can this be explained?
One was born on Feb 28, 1999 just before midnight. The other was born 5 minutes later on Mar 1, 1999.
However, the year 2000 is a leap year and Feb 29 had to occur before the second twin could celebrate their birthday.