Noun and の adjective
たいりく
ムー大陸って本当に実在したんですか？
Did the continent of Mu really exist?
A big land is the biggest types of land on this earth that there are. That is a continent.
This is a jukugo word, which usually means on'yomi readings from the kanji. If you know the readings of your kanji you'll know how to read this as well.