On Sept. 14, a major Saudi oil processing plant was rocked by a series of explosions. The facility, and another oil field to the south, had been attacked from the air. Here's what we know — at this time — about the attacks based on physical evidence.

The strike was large and sophisticated

Emergency sirens wailed on Hawaii's Oahu and Maui islands Wednesday evening, warning of a tsunami, but the alert turned out to be a mistake. The error sparked anger from residents who recalled a similar false warning last year of an imminent ballistic missile attack.

Within minutes of the alarm going off shortly after 5 p.m. local time (11 p.m. ET), authorities were trying to calm the public by getting out word of the mistake.

America's best-known obelisk reopens to the public on Thursday after more than three years of construction on a new security facility and renovations to its elevator system.

The Washington Monument will again welcome visitors up to its observation deck, where, from more than 500 feet in the air, visitors can see national landmarks including the U.S. Capitol, Washington National Cathedral, Ronald Reagan Washington National Airport, the Lincoln Memorial and the Jefferson Memorial.

But first, you have to go through security.

Updated at 11:20 a.m. ET

House Speaker Nancy Pelosi, D-Calif., unveiled her long-anticipated plan to lower the cost of prescription drugs on Thursday. It is a priority shared by President Trump, fueling a glimmer of hope that there is a deal to be had on the issue ahead of the 2020 elections.

"It is transformative," Pelosi said of her plan."We do hope to have White House buy-in."

One of America's most recent espionage cases started with a friendly hello over the Internet.

It ended with a jury in Virginia finding former CIA officer Kevin Mallory guilty of spying for China. The Mallory case — a rare counterintelligence investigation to go to trial — provides a lesson in how Chinese spies use social media to try to recruit or co-opt Americans.

For the head of the Justice Department's National Security Division, John Demers, it also highlights a broader point.