One of the best meteor showers of the year coincides with Earth Day this year — meaning people all over the world will have the chance to see the 2018 Lyrid meteor shower light up the sky.

The annual Lyrid meteor shower already started last weekend and will continue through the end of April, though peak viewing hours will begin the evening of Saturday, April 21 and extend through the morning of Sunday, April 22 (Earth Day). During its peak, the Lyrid meteor shower is expected to bring up to 20 meteors per hour, according to AccuWeather.

Here’s everything you need to know about the 2018 Lyrid meteor shower, including the best times and places to view it:

What time is the Lyrid meteor shower?

According to a video from NASA’s Jet Propulsion Laboratory, the Lyrid meteor shower is active from Saturday, April 14 through Monday, April 30. But in the Northern Hemisphere, it peaks in the early morning hours of Sunday, April 22.

Those who want to view the Lyrid shower should find an area away from light pollution (meaning it won’t be as visible to city dwellers in major cities like New York City, Boston and San Francisco) on the night of April 21. While a few meteors may be spotted late at night on Saturday, light from the waxing moon may interfere with visibility. After the moon sets at around midnight local time, visibility should improve, and stargazers should be able to see meteors during the few hours before sunrise on Earth Day.

“In a moonless sky, you might see from about 10 to 20 Lyrid meteors an hour at the shower’s peak on the morning of April 22,” Bruce McClure writes for EarthSky.

Where is the best place to see the meteor shower?

Special equipment — telescopes, binoculars — is not necessary to view the Lyrid meteor shower, which is safe to view with the naked eye. However, to increase your chances of seeing this annual meteor shower, it’s best to head to a dark area away from light pollution.

“Clear dark sky away from city lights,” is what the lead of NASA’s Meteoroid Environment Office Bill Cooke, Ph.D. suggested in an email to Fortune. “Lie flat on your back and look straight up—give yourself about 30-45 minutes for your eyes to adapt to the dark.”

And while the Lyrid meteor shower should be viewable no matter your location, there are a few other variables to take into consideration: hemisphere and weather. For those in the U.S., AccuWeather has a map showing what areas of the country will have good, fair, or poor conditions for viewing. According to the map, those with the best optics for viewing the Lyrid meteor shower are on the East Coast from Pennsylvania to Maine as well as a swath on the West Coast that includes parts of Texas, Arizona, New Mexico, Nevada, Washington and California.

The Lyrid meteor shower “favors the Northern Hemisphere,” according to EarthSky’s McClure, because “the higher [the star] Vega climbs into your sky, the more meteors you’re likely to see.” Vega is part of the constellation Lyra — where the Lyrids get their name, because it looks like they are radiating from the constellation — and it is located in the Northern Celestial Hemisphere.

However, those in the Southern Hemisphere will have to wait until the “early hours of the morning before reasonable rates can be observed,”according to the Australian Broadcasting Corporation. Viewers in Australia will have the best view of the meteor shower on Monday, April 23 between 2 a.m. and 4 a.m. local time.

And Cooke cautions that usually only the “two biggest annual showers (Perseids and Geminids) live up to public expectations.”

What is the Lyrid meteor shower?

The Lyrid meteor shower happens annually, and according to a video from NASA’S Jet Propulsion Laboratory, it is active from April 14 until April 30 — and peaks on April 22.

It is the “first significant meteor shower in a few months,” according to AccuWeather’s astronomy blogger Dave Samuhel. And while it is only a moderately active meteor shower, it is the oldest one on record and was first recorded by the Chinese in 687 B.C.

What stargazers see when they’re observing the Lyrid meteor shower is the Earth’s orbit coming into contact with dust left behind from a comet — in this case Comet Thatcher (C/1861 G1), which was discovered in 1861 by A.E. Thatcher. Comet Thatcher orbits the sun roughly every 415 years, according to NASA. The debris left behind by the comet burns up in our atmosphere creating fiery streaks observed in the night sky.