Every September, New York City becomes even more international than usual as world leaders, diplomats, journalists and delegations arrive for United Nations week.

The annual gathering surrounding the United Nations General Assembly brings representatives from around the globe to UN Headquarters on Manhattan’s East Side. For New Yorkers, it’s one of those weeks when global politics and everyday city life collide — sometimes quite literally in Midtown traffic.

With presidents, prime ministers and other high-level officials moving throughout Manhattan, expect increased security, street closures and traffic disruptions, particularly around the United Nations complex along First Avenue. Midtown East typically sees the biggest impact, but motorcades and security measures can create delays well beyond the immediate UN area.

For anyone heading into Manhattan this week, public transportation is likely the safest bet. Drivers should allow extra time, especially when traveling across Midtown or near the East Side.

But UN week is about much more than traffic.

The influx of international visitors creates a noticeable buzz throughout the city. Hotels fill with delegations, restaurants host diplomatic dinners and private events, and venues across Manhattan welcome receptions, panels, networking events and gatherings tied to the General Assembly.

It’s also a particularly active week for New York’s hospitality and events industries. Many organizations use the concentration of global leaders, business executives, nonprofit organizations and media in one place to host their own events alongside the official UN schedule.

That means the activity surrounding the General Assembly often stretches far beyond the UN campus. Midtown hotels, rooftop venues, restaurants and event spaces become part of an unofficial citywide extension of the week’s proceedings.

For New Yorkers who aren’t attending any of those events, there’s still something uniquely New York about seeing the city temporarily become the center of global diplomacy. You might find yourself sitting in traffic because a head of state is passing by — and then grab a slice of pizza five minutes later like it’s any other September afternoon.

It can be inconvenient, fascinating and chaotic all at once.

In other words, it’s a very New York kind of week.