Mayor Cesar Maia kicked off Rio de Janeiro's annual carnival Tuesday by handing over the key to the city to the Rei Momo, or carnival king, and jokingly putting him in charge of solving the city's problems.

"When I hand the key over to the Rei Momo all the questions facing the city become his responsibility," Maia said, suggesting that the Momo would take care of civil servants' low salaries and potholes with a wave of his scepter.

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The carnival king and queen rode in with their princesses in a horse-drawn carriage in the pouring rain to receive the key at the City of Samba, a complex of warehouses where top samba groups prepare their floats.

Despite the official carnival opening — four days earlier this year — banks, businesses and government offices remain open this week. The high point of the celebration starts Sunday, when the city's top 12 samba groups mount 80-minute long parades in hopes of being declared this year's champion.

In most Brazilian cities, the celebrations run until Ash Wednesday, when Catholics traditionally give up meat and promise to live more circumspectly. In Salvador da Bahia, the celebrations run beyond Ash Wednesday, despite church protests.

Salvador had a minor controversy when its Rei Momo, Clarindo Silva, weighing just 128 pounds, was elected king despite a city requirement that the Momo weigh at least 265 pounds.

Exclusively fat carnival kings have been a thing of the past in Rio since 2003 when Maia, in a bow to public concerns about growing obesity, relaxed a requirement that Rio's carnival king weigh over 300 pounds.

Alex de Oliveira, serving as Rio's carnival king for the 10th consecutive year, once weighed as much as 500.44 pounds but has trimmed down to 161 pounds through stomach-staple surgery.

To be declared carnival king, a candidate must display charm and personality — and know how to dance the samba.