Global leaders descend upon midtown Manhattan this week for speeches, meetings and receptions, an annual migration to the United Nations meant to tackle the world’s biggest problems. It’s an event that New Yorkers have come to dread.

President Joe Biden arrived Sunday night for the start of the Sept. 19-26 U.N. General Assembly session. The leaders of China and Russia won’t be attending, but Iran’s President Ebrahim Raisi will — a decision that’s expected to trigger a protest near U.N. headquarters. All in all, some 150 leaders are expected in the city, a recent record.

Those protests, along with demonstrations against climate change, will snarl traffic across the East Side, where roads have been blocked off around the U.N. and many of hotels where country delegations will camp out. The presence of all those diplomats and staffers has pushed hotel rates to three to five times their average.

For all the commotion, weighty issues will be discussed. President Volodymyr Zelenskyy, who’s also in town, is looking to keep up allied support for his defense against Russia’s invasion, and hopefully woo new allies like Brazil’s President Luiz Inácio Lula da Silva. Small island nations in the Pacific Ocean will urge others to take action on rising ocean levels and other symptoms of climate change that threaten their very existence.

Here’s what to watch during this hectic week in New York:

Ukraine

Zelenskyy is expected to attend the high-level debate in person, addressing the General Assembly and, along with his Western counterparts, making the case for continued economic and security assistance. His visit comes against the backdrop of a grinding Ukrainian counteroffensive and a looming spending fight in the U.S. Congress, where segments of the Republican Party have questioned the costs of U.S. support.

The Ukrainian leader will also address a meeting of the powerful U.N. Security Council meeting on Wednesday in a push to persuade countries in the so-called Global South that Russia bears responsibility for the economic instability and food insecurity they’re facing.

He is also set to meet this week with Brazil’s Lula, one of the most high-profile emerging market leaders who has refrained from condemning Putin’s invasion.

North Korea

Pyongyang repeatedly has defied U.N. Security Council resolutions in its pursuit of a nuclear weapon, while resisting U.S. efforts at diplomacy. Kim Jong Un’s recent summit with Russian President Vladimir Putin sparked fresh concerns about military cooperation between the two countries, including potential North Korean assistance in Russia’s war on Ukraine.

Iran

Five American citizens held in Iran — one for eight years — headed back to the U.S. on Monday as part of a prisoner swap between Washington and Tehran. The exchange follows complicated maneuvering to give Iran access to $6 billion in proceeds from its sale of oil to South Korea.

With Iran’s Raisi coming to New York, there may be the possibility of new diplomacy over Iran’s nuclear program. The U.S. says there won’t be face-to-face meetings, but the agreement could unlock a new round of talks.

Lula

Lula is back and, as is tradition for his country since the early days of the U.N., will deliver the opening speech at the General Assembly. Lula is expected to push for a new model of global governance, as he has been repeating around the world that the U.N. “needs to regain representation” and that forums like the Security Council have their limitations, evidenced by the failure to end Russia’s war in Ukraine.

The environmental agenda will also play a leading role in Lula’s speech as he seeks international assistance protecting the Amazon rainforest and attempts to refocus his foreign policy agenda toward an issue that won him global acclaim after his 2022 election victory. Despite being at odds over the war and relations with China, Lula and Joe Biden are expected to hold an event on the sidelines of the assembly, where they plan to call for improved working conditions in the U.S. and Brazil.

The other events

It’s often said that the real action during U.N. General Assembly week is all the events that happen on the sidelines, and that’s certainly the case this year.

Biden is set to meet with Israel Prime Minister Benjamin Netanyahu on Wednesday as the U.S. looks to persuade its increasingly reluctant ally to ease tensions with the Palestinians and weigh normalization with Saudi Arabia.

The Clinton Global Initiative holds its annual meeting with Pfizer CEO Albert Bourla and World Bank President Ajay Banga expected to speak. And Bloomberg LP, the owner of Bloomberg News, hosts a Transition Finance Action Forum to push for a faster global net zero economic transition.

All that traffic

New York City is recommending you don’t even try to drive into the city. Already, entire sections of the East Side near U.N. headquarters have been blocked off. The Intercontinental Hotel, home this week to several world leaders, is surrounded by massive dump trucks that serve as blast walls on wheels.

Extra police officers will be deployed from 34th Street to 65th Street as the city struggles to cope with the estimated 150 world leaders set to be in attendance.

Every day this week has been labeled a “Gridlock Alert Day,” when the city advises commuters to “consider walking, biking, or taking mass transit for any trips in Manhattan.”