Want to be featured on 500px ISO? Every week, we’ll announce a new photo challenge theme. You’ll have until next Tuesday, November 25 to submit your photo as an entry. You may already have an existing photo that fits the theme, or you can take this as a challenge to shoot and upload a new photo.

To skip to the new theme for next week, click here.

This Week’s Blue Hour Photo Contest Winners

Last week, we asked you to share with us your best Blue Hour photos. Blue Hour is the time of the day that is just before sunrise and just after sunset. When the sun is at a distance below the horizon, the indirect sunlight takes on an ethereal blue hue. This light is known for producing the best quality in photos, so most photographers also call it, “sweet light”.

We’ve received more than 700 amazing photo submissions last week. Thank you to those who took the time to submit their shots! To view all the photo submissions, you can visit the Blue Hour contest gallery. From “bolt-of-blue” seascape lightning strikes to panoramic city skylines, here are the 500px team’s 25 favorite Blue Hour images-scroll down!

A T T A C K by Thomas Roux on 500px.com

Photograph A New Day Is Born by Stian Klo on 500px

Twilight colors by Shreenivasan Manievannan on 500px.com

?he "golden" Castle by George Papapostolou on 500px.com

Wellington Twilight From The Tararua Ranges by Mark Gee on 500px.com

Black sea- blue skies by Baltas Guilkos on 500px.com

Light-Lapse... by Charlie Joe on 500px.com

Porto Arabia by Hammad Iqbal on 500px.com

Portland Skyline from Pittock Mansion by Matt Payne on 500px.com

Gent by John Monster on 500px.com

Frigid Dawn by TJ "TJ Thorne" Thorne on 500px.com

The Path to God by Hammad Iqbal on 500px.com

Lonely Island by Tobias Roetsch on 500px.com

Détail Tour by Jason Waltman on 500px.com

a romantic evening by Rachna Nagarajan on 500px.com

Night swimming by Alexandre Minard on 500px.com

Trillium Blues by Shreenivasan Manievannan on 500px.com

when sea takes over by Anita Palceska on 500px.com

Ponte Vecchio - Firenze by David Saliba on 500px.com

birds by Alper Doruk on 500px.com

Deep blue by Miguel Angel Martín Campos on 500px.com

Heaven on a Lake by Brian Hammonds on 500px.com

Ghost Tower by Alexander Riek on 500px.com

Blue Hour Lightning by Jeff Sullivan on 500px.com

Hole In The Rock by Mark Gee on 500px.com

Serene by Malcolm Lowery on 500px.com

Awesome Subscription Giveaway Winner

Every week, we hold a random draw giveaway for all those who enter the contest. Anyone who enters will have the chance to win two months of free Awesome membership! This week’s lucky random winner is Eileen Bauer. Congrats, Eileen, we’ve just upgraded your account!

Next Week’s Theme: Festive

Next week marks Thanksgiving in the United States. Though it’s an American holiday, acknowledging what we are thankful for and gathering with loved ones are universal traditions that anyone can observe—and totally worth celebrating at least once a year.

So we thought it’s time to get festive! Even if you’re not celebrating with a Thanksgiving feast next week, we’d love to see photos of the fantastic festive moments you’ve captured on camera. Whether it’s fireworks exploding in the sky, a bokeh image of a city skyline, a delicious dinner tablescape, wild street parties, confetti at a concert, or a fun wedding portrait—share with us your best festive photos!

1. Shoot a photo that fits this theme.

2. Upload the image on 500px, or select a photo you’ve already uploaded to your 500px page.

3. Add the tag #500pxFestive to your photo descriptions. To learn how to add tags to your photo, click here.

4. You’re done! Track all entries here.

Deadline is November 25th at 11:59 P.M. Pacific Time. For inspiration, check out these photos:

14 juillet 2013 by _PEC_ on 500px.com

Celebration by Keda.Z Feng on 500px.com

Shampagne by Ruslan Grigoriev on 500px.com

Giuseppe Ottaviani by Michel van Rossum on 500px.com

Celebrating Missy

Good luck, everyone! We’re excited to see how you party!