Rescue officials in Poland are working quickly to clear one of the country’s highways. The roadway is covered with a sticky brown substance. It is blocking cars from both directions. What is causing the mess? Milk chocolate. The problems began early Wednesday, after a huge vehicle carrying many tons of liquid chocolate overturned. Chocolate spilled out. It spread across six lanes of Poland’s A2 highway. The liquid chocolate solidified as it cooled, causing even more difficulties.