In western countries Christmas lights strung up both inside and outside the house are a common sight. Heidi Davis presented a brief history of the lights. Highlights include:

• People used to decorate their trees with lit candles. A bucket of water was kept on hand in case the tree ignited.
• Electric Christmas tree lights didn’t gain popularity until 1895 when American President Grover Cleveland displayed the first electronically lit White House Christmas tree.
• During World War Two the Rockefeller Centre Christmas lights remained unlit – in keeping with wartime blackout regulations of the time.

Read more about the history and present of Christmas tree lights over here.

Source: Popular Mechanics