(CNN) -- The opening day of the World Cup brought joy and sadness to the host nation as Brazil won its first game, rallying to defeat Croatia 3-1.
But it was a day marred by a small, but contentious, protest over the billions spent on the sports spectacle.
Here are five things that happened Thursday as the first ball was kicked in Sao Paulo.
The most expensive World Cup is underway. Brazilian officials shelled out $11 billion on the tournament, three times what organizers in South Africa spent for the 2010 Cup. Not surprisingly, there are Brazilians who believe the money could have been better spent.
With reporters descending on Sao Paulo for the opening match, protesters tried to make their way toward Arena Corinthians stadium and were met by tear-gas firing riot police.
The cops' goal: To keep the demonstrators from reaching the main avenue, leading to the stadium.
It wasn't a big protest, but it was met with a big response. At least one person appeared to be arrested. Several people were injured, including a CNN producer and reporter.
The best kick of the day went perhaps two yards.
A paraplegic, identified by the BBC as 29-year-old Juliano Pinto, wore an exoskeleton and a blue cap fitted with electrodes. The electrodes helped him use his brain to control the exoskeleton to take a few steps and take the ceremonial first kick before the opening match
It went about 6 feet before a ball boy scooped it up and took it to the center of the match officials.
"We did it!!!" Dr. Miguel Nicolelis tweeted.
Nicolelis, a Brazilian-born neuroscience professor at Duke University, and a group of scores of scientists developed the exoskeleton after they decoded the alphabet of neurons in the brain and figured out how to transmitted the mind's language to devices outside the brain.
That penalty that everyone is talking about, the one that should never have been given, well, it should probably have been stopped.
It was a double punch in the gut for Croatian fans.
First, referee Yuichi Nishimura awarded Brazil an undeserved penalty kick. It seemed obvious to almost everyone watching the match that Brazilian striker Fred went down in the penalty area on his own, but Nishimura must have thought there was contact from a Croatian defender.
Then when Neymar's hit his spot kick, goalkeeper Stipe Pletikosa guessed correctly and got a hand on the ball -- but he couldn't stop it from going in the goal.
Croatia's coach didn't worry about any fines from FIFA after the match for critical remarks against the referee.
"It's ridiculous. If we continue in this way, we will have a circus," said Niko Kova, according to Yahoo Sports. "If that's how we start the World Cup, then we may as well give up and go home now."
Maybe it's time for a manager's challenge and instant replay?
When doves die
You release three doves in an open-air stadium with 60,000 screaming people and helicopters circling overhead, what could go wrong?
Well, it appears from media reports that at least one -- possibly two -- didn't live to see themselves home.
One dove took a header into the stands almost immediately after liftoff, wrote the New York Times. Other media reported a second crashed.
But there was good news.
"Exciting dove update," tweeted Hadley Freeman of the Guardian newspaper, "The one remaining dove has flown into the press box!"
It wasn't the first misstep of the day. During the opening ceremony, the motorized stage riser hiccupped as rapper Pitbull and singer Jennifer Lopez ascended from inside the setup. At one point, it even appeared it might sink back under the stage. But it stopped and Pitbull stepped up a few feet and, once out, helped JLo out from the hole.
The United States, which plays it first match of the tournament on Monday, wanted to have a private scrimmage against Belgium on Thursday.
But with a transit strike making bad traffic worse, Belgium coach Marc Wilmots and U.S. coach Jurgen Klinsmann agreed to call off the match, Sports Illustrated reported.
Belgium camp is 32 miles from canceled game at US base. Surprised Klinsmann didn't offer to use his helicopter pilot skills to give a ride.— Grant Wahl (@GrantWahl) June 11, 2014
Perhaps they should have rescheduled and traveled during the Brazil-Croatia match; the roads of Sao Paulo were practically empty then.
Except for the protesters and riot police ...