North Korea conducted its 10th missile test on Saturday. It was a major turning point in North Korea’s missile program — and potentially its nuclear program too.

The tested projectile, the Hwasong-12, is a brand new intermediate-range ballistic missile (IRBM) in North Korea’s arsenal — and it did better than any missile the country has ever tested. It was purposely shot at a high angle to avoid directly hitting a surrounding country, but it still traveled 489 miles and got as high as 1,312 miles, according to North Korea’s state-run news agency — and landed near Russia. If it were fired properly, it could have traveled about 2,500 miles, according to experts.

This is a really big deal: It means that North Korea’s threats that it can hit US territory aren’t so empty anymore. Guam — which is a US territory and is home to Andersen Air Force Base — is now within Pyongyang’s reach. And according to a North Korean statement (always to be taken with a grain of salt), the Hwasong-12 can carry a nuclear warhead.

As if that were not frightening enough, this test also allows North Korea’s rocket scientists to learn valuable lessons to better build an intercontinental ballistic missile (ICBM) to hit the US mainland — North Korea’s top priority.

The test “represents a level of performance never before seen from a North Korean missile,” aerospace engineer John Schilling writes on the US-Korea Institute’s blog 38 North. And that might even be an understatement.

In its own way, North Korea warned us this moment was coming. It turns out that Pyongyang showcased the Hwasong-12 during its big April 15 military parade.

And after a March high-thrust rocket engine test, North Korean leader Kim Jong Un said “the whole world will soon witness what eventful significance the great victory won today carries.”

Here’s a photo of Saturday’s missile launch from South Korea’s Yonhap News Agency:

Looks like liquid engine with 2 or 4 vernier engines (can't quite see). Single stage missile (suspicious). #DPRK pic.twitter.com/Uw1Bvce7rb — Melissa Hanham (@mhanham) May 14, 2017

Consider it witnessed.

North Korea’s missile program is improving quickly

There’s no question that North Korea has made significant leaps forward in its missile program. The Wall Street Journal reports that “in the past three years, North Korea has launched more major missiles than in the three previous decades combined.”

Kim has emphasized the development of the country’s nuclear program since he took power in 2011. By building a highly capable missile and nuclear program in tandem, he believes, North Korea can sidestep America’s threats and deter any action against it.

But the recent test will only worry US and regional leaders more. South Korea just elected a new president, Moon Jae-in, and this missile test was widely seen as Pyongyang’s attempt to test his resolve. Moon wants more economic ties with North Korea as well as more dialogue, but he said the recent test will be met with “stern responses.”

Russian President Vladimir Putin called the test “dangerous”—recall the missile landed outside Russian territory—but he also warned the United States and others against “intimidating” North Korea.

For his part, President Donald Trump responded to this latest test with a renewed call for tougher sanctions against North Korea to halt its program, but that tactic has historically failed. After all, North Korea continues to test better and better missiles despite the harsh sanctions that have already been imposed, especially since its first nuclear test in 2006.

In the meantime, the CIA has established a brand new Korea Mission Center to keep tabs on the latest North Korea developments.

If something is to be done about the program, it would need to be done quickly. American troops are in harm’s way in South Korea, Japan, and now Guam. And most experts believe that North Korea could have a nuclear-tipped missile capable of hitting Seattle within about five years.

But even that timeline might be too optimistic. Mira Rapp-Hooper, an Asia and nuclear expert at the Center for a New American Security, told me that “this new missile suggests that [North Korea’s] programs are advancing quickly, and an ICBM may be only a year or so away.”

In other words, America’s mainland cities could be within North Korea’s reach in only a year’s time.

And so what at first appeared to be just another run-of-the-mill missile test has turned out to be one of the most stunning and dangerous reminders of the quick growth of North Korea’s nuclear and missiles programs.

Those who said North Korea would be the top national security challenge facing the Trump administration — like former President Barack Obama — appear to have been correct.