The US might have the White House, but Argentina has the Pink House. The Casa Rosada at the eastern extreme of the Plaza de Mayo is the seat of the country's government, where the President and her staff work. On weekends, you can tour the building for free.
Are 24 hours enough to become enamored of a new city? Well, Buenos Aires worked its magic quickly on us. After a long flight and a stressful process to get our dog through customs, we didn't get into our place until very late, with just enough energy to fall into bed. But the next day, we awoke to sunny weather and the stress melted away.