The medialuna is one of the most popular things to eat in Argentina, even though it wasn´t invented here and you can find versions of it throughout South America. In Argentina, these pastries are only rivaled by alfajor cookies and empanadas in terms of their ubiquity. They are the smaller, sweeter South American cousins to the French croissant.
In Buenos Aires there are two peak times of the day in which people enjoy medialunas. The first one is breakfast, so the bakeries or panaderias will have a morning rush, as well as the restaurants and cafés that offer them. The second instance is late afternoon tea time of 5pm. However, you will rarely find a café empty in between. There is probably someone enjoying a medialuna in the city at every hour of the day somewhere among its many coffee shops, offices or homes.