Q: This task is about reading the given passage and construct a question about the information present in the passage. Construct a question in such a way that (i) it is unambiguous, (ii) it is answerable from the passage, (iii) its answer is unique (iv) its answer is a continuous text span from the paragraph. Avoid creating questions that (i) can be answered correctly without actually understanding the paragraph and (ii) uses same words or phrases given in the passage.
On 11 March 1978, a PLO guerilla raid from Lebanon led to the Coastal Road Massacre. Israel responded by launching an invasion of southern Lebanon to destroy the PLO bases south of the Litani River. Most PLO fighters withdrew, but Israel was able to secure southern Lebanon until a UN force and the Lebanese army could take over. The PLO soon resumed its policy of attacks against Israel. In the next few years, the PLO infiltrated the south and kept up a sporadic shelling across the border. Israel carried out numerous retaliatory attacks by air and on the ground.
A:
When did the Coastal Road Massacre occur?