The 120-mile-long artificial waterway known as the Suez Canal has been a potential flash point for geopolitical conflict since it opened in 1869. Now the canal, a vital international shipping passage, is in the news for a different reason: A quarter-mile-long, Japanese-owned container ship en route from China to Europe has been grounded in the canal for days, blocking more than 100 vessels and sending tremors through the world of maritime commerce.

Here are some basics on the history of the canal, how it operates, how the vessel got stuck and what it means.

Where is the Suez Canal?

The canal is in Egypt, connecting Port Said on the Mediterranean Sea to the Indian Ocean via the southern Egyptian city of Suez on the Red Sea. The passage enables more direct shipping between Europe and Asia, eliminating the need to circumnavigate Africa and cutting voyage times by days or weeks.

a description of the canal by GlobalSecurity.org.

estimated 1.5 million workers.

According to the Suez Canal Authority, the Egyptian government agency that operates the waterway, 20,000 peasants were drafted every 10 months to help construct the project with “excruciating and poorly compensated labor.” Many workers died of cholera and other diseases.

Political tumult in Egypt against the colonial powers of Britain and France slowed progress on the canal, and the final cost was roughly double the initial $50 million projected.

Which country controls the canal now?

The British powers that controlled the canal through the first two world wars withdrew forces there in 1956 after years of negotiations with Egypt, effectively relinquishing authority to the Egyptian government led by President Gamal Abdel Nasser.

first-ever peacekeeping force to the area. The outcome was seen as a triumph for Egyptian nationalism, but its legacy was an undercurrent in the Cold War.

The Suez crisis was also a theme in Season 2, Episode 1 of “The Crown,” the acclaimed Netflix series about Britain’s royals, as the British prime minister at the time, Anthony Eden, struggled over how to respond.

Has the canal ever been closed since then?

Egypt closed the canal for nearly a decade after the 1967 Arab-Israeli war, when the waterway was basically a front line between Israeli and Egyptian military forces. Fourteen cargo ships, which became known as the “Yellow Fleet,” were trapped in the canal until it was reopened in 1975 by Mr. Nasser’s successor, Anwar el-Sadat.

A few accidental groundings of vessels have closed the canal since then. The most notable, until this week, was a three-day shutdown in 2004 when a Russian oil tanker ran aground.