英國哈普爾山的一個前石灰石采石場旁邊有一個美麗的藍湖，當地的警察卻把它染成了黑色，原因何在？

Not even a nationwide lockdown could stop England's Instagrammers from flocking to a former limestone quarry in Harpur Hill， whose bright blue waters have earned it the nickname， “Blue Lagoon”.

So the police did what they could to stop visitors from coming. They dyed it black.

Months ago， UK's Prime Minister Boris Johnson banned residents from leaving their homes to prevent the spread of the novel coronavirus.

“If you don't follow the rules， the police will have the power to enforce you，” said Johnson， who himself has tested positive for coronavirus.

Despite this order， the police said people were still visiting the quarry， which has not been used for some time and become a popular tourist attraction.

“With this in mind， we have attended the location this morning and used water dye to make the water look less appealing，” the Buxton police department said in a Facebook post Wednesday. “Please stay at home.”

This isn't the first time the picturesque body of water， near Buxton and northwest of London， has been dyed black， according to the police. While the lagoon may look like a tropical getaway， officials say the water contains toxic chemicals and has a pH level of 11.3， according to the BBC. For reference， laundry bleach has a pH level of about 12.

Signs around the lagoon even warn tourists that the water contains cars， dead animals and trash. So the police regularly dye the water to prevent people from swimming in it. The move by Buxton police came when the novel coronavirus broke out in the UK and the number of confirmed cases and deaths continued to rise.

Johnson said he would send a letter to 30 million households across the UK to urge people to stay at home.

“We know things will get worse before they get better，” he wrote in the letter. “But we are making the right preparations， and the more we all follow the rules， the fewer lives will be lost and the sooner life can return to normal.”

Reading check

Why do you think the police dyed the “Blue Lagoon” black？

____________________________________________