Professionals and amateur photographers can enter a contest.

The winner of the contest will appear in the March edition of National Geographic. The theme of the contest is "cities" and the complete guidelines for submitting photos are available here.

Each day, editors pick a dozen top photos which are then voted on by readers of the website to arrive at the best photo of the month.

Any nationality may participate, but photographers must be over the age of 18. Photos can be digital or digital scans and only one entry is permitted per person in the monthly contest. All winners retain ownership of copyright.

For more information, click here.

Source: Ijnet