Mars: Hellas Planitia. The largest visible impact crater in the Solar System is Hellas Planitia on Mars, a giant depression with a floor over seven kilometres (4.3 miles) below the Martian surface.
Dimensions. The recommended size for one parakeet is 25 inches tall and 25 inches deep. To house two birds comfortably, you should double that cage size to make it at least 50 inches tall and 50 inches deep.If you can afford it and have enough space, opt for a bigger cage.all cages work best for parakeets. This type of bird really likes to fly around and hop from place to place. If you can, choose a cage that exceeds the height recommendation of 50 inches.
The following guidelines will help you to work out the minimum size of the home cage environment you should have for your pet birds: 1. The minimum width of a cage for a pair of birds should be three times their combined wing span.2.The minimum length of a cage should permit at least 2 wing beats (the more the better) between perches.he following guidelines will help you to work out the minimum size of the home cage environment you should have for your pet birds: 1. The minimum width of a cage for a pair of birds should be three times their combined wing span.