Maybe the sudden rise of the walls at the end represents Brasília and bureaucracy:
''From the beginning, the growth of Brasília was greater than original estimates. According to the original plans, Brasília would be a city for government authorities and staff. However, during the construction period, Brazilians from all over the country migrated to Brasília, seeking public and private jobs.
At the close of the 20th century, Brasília held the distinction of being the largest city in the world which had not existed at the beginning of the century. Brasília has one of the highest population growth rates in Brazil, with annual growth of 2.82%, mostly due to internal migration.''