Participants at the United Nations Climate Change Conference in Cancun, Mexico are complaining about long delays amid heavy security. Some environmental activists say they are being kept well away from conference sites, and when a group tried to stage a protest in front of the main conference hotel, security guards forced them to leave. But, there are good reasons for such measures in Mexico.
Mexico is trying to be a good host to people who have come to this conference from around the world. And Mexico wants them to leave with a good impression.
So Mexican Foreign Minister Patricia Espinosa is upset by criticism of logistics at this event.
"I would like your understanding," she said. "I can assure you that we are going to do our best to accommodate you."
What led to the gripes is this - getting up and down the narrow highway that connects Cancun's hotel zone with the conference site can take a good part of the day.
Even moving from one part of the conference zone to another means going through security much like at an airport.
Sena Alouka from Togo says he and his African colleagues noticed a lot more guns on display than at previous conferences.
"For us, it is like you are seeing those old Zapata movies from the bush of Latin America," he said. "We see for the first time.. for us, it is really funny for us to see them heavily armed."
There is tight security at this conference here in Cancun, partly because Mexico is undergoing a wave of violence connected with the war on drugs that has claimed over 28,000 lives in the past few years.
Far from the conference halls, many parts of Mexico have come to resemble war zones, with open gun battles and car bombs.
Mexican federal police and soldiers have had notable successes in recent weeks, killing and capturing major drug traffickers.
But some parts of the country remain unstable.
Cancun has seen little violence and its beaches seem far removed from anything unpleasant.
Visitors from countries that have gone through their own waves of violence understand the precautions.
This woman from Peru says Mexico is doing what it must.
"It depends on the situation and they are being cautious and I can understand that," she said.
Whatever is happening in other parts of Mexico, the scene at this conference is peaceful.
And that's the way Mexican officials say they want it to be.