Argentina has come to a near standstill as authorities carry out the official 10-year census.
Tens of thousands of questioners have been recruited to visit every home in the land, from the northern border with Bolivia to Argentine Antarctic bases.
According to the last census nine years ago, there are about 41 million people living in Argentina.
But that survey was fraught with difficulties, carried out in the midst of economic and political crisis.
This census is designed to be more thorough.
Only essential services are allowed to remain open while an army of questioners covers the country, including shanty towns, prisons, homes for the elderly and psychiatric hospitals.
Argentina has many remote regions and some surveyors started work early to reach indigenous communities high in the Andes mountains and took boats to some of the countless islands in the River Plate delta.
The census is being carried out by the National Statistics Office, known as Indec by its Spanish initials, which critics have accused of publishing misleading inflation and poverty figures that favour the government.
Argentina is also suffering rising crime rates and several community organisations have expressed concern about residents allowing strangers into their homes.
The Argentine authorities said they would meet those concerns by deploying tens of thousands of police and military on the streets and with identification for the census workers that was impossible to counterfeit.
And some early results have already been revealed. There are 230 Argentines, including 16 children, living on six bases in Antarctica.
They are also conducting a census of penguins on the frozen continent. Those results are not in yet, although they do know that the feathered folk greatly outnumber the humans.