That's why I still keep a landline, though the family rarely uses it. It so happened that my family was debating why we need a landline when each of us has one or two mobile connections. Co-incidentally, the next day a major city got flooded. Nearly all the cell towers in the flooded area got knocked out because the generators / UPS of the towers all conked out. Only the wired landlines worked. We all voted to keep the landline. (It also turned out to be a blessing because in some forms of the US embassy, landline is a required field).