Explanation:

Statement 1 and 2: A cutting edge physics experiment, it is unlike a round normal- looking observatory. It is L-shaped and comprised of two enormous laser interferometers located thousands of kilometers apart.
Statement 3: LIGO exploits the physical properties of light and of space itself to detect and understand the origins of gravitational waves.
But, unlike optical or radio telescopes, LIGO cannot see electromagnetic radiation (e.g., visible light, radio waves, microwaves) nor does it have to because gravitational waves are not part of the electromagnetic spectrum.
In fact, electromagnetic radiation from space is so unimportant to LIGO that it is completely isolated and sheltered from the outside world.
Learning: Gravitational waves can be explained as ripples in the fabric of space-time which can only be caused by massive astronomical events such as neutron stars or black holes orbiting each other so that these waves would finally radiate from them.