Iguana

 The Green & Red Iguana is a large lizard reaching sizes of 4 to 6 feet.  There native habitat is in Central to South America and live in a tropical existence.  Iguanas under the right conditions in captivity can live around 12 to 15 years.  Iguanas are an arboreal animal (lives in trees).  Some species once they hatch climb into the trees and never set foot on the ground again their whole lives.  
The Green Iguana is a greenish grey color with black stripes that has 5 toes on each foot.  The Red Iguana is nothing more than a color variation of the green.  It still retains the black body stripes but has a red tinge to them and the body is predominantly red instead of green.  Red Iguana still do retain some green areas on their body, usually the underbelly can be spotted with green.  This area could be either small or large.  The tail generally is about 3 times the length of the body.  They sport a flap of skin below the chin commonly referred to as a Dewlap.  They have a spiny looking crest that extends the length of the body.

Enclosure

You want to make sure that your iguana has ample amount of space in there enclosure with lots of climbing space.  A good rule of thumb for a full grown iguana of 6 feet is an enclosure of 9 feet long 4 feet wide.  In their enclosure you would want to provide shelving and branches for them to climb around on.  Unless trying you hand at breeding the iguana it is best to house these big guys by their selves.

Temperature/Heating & Humidity

The daytime temperature should be kept between 80 to 95 degrees with a basking area reaching from 95 to 100 degrees.  There basking area should be at one end of the enclosure to have a thermal gradient in the enclosure as iguana's will self regulate their body temp.  There evening temperatures should be between 70 to 75 degrees. 

Full Spectrum UV lighting should be provided with a bulb that produces both UVA and UVB lighting.  This will allow the iguana to produce its own D3 to aid in the absorption of calcium into the body for proper bone development.  A good rule of thumb is at least 12 hours of daylight and 12 hours of night time.
Since iguana's come from a tropical are we need to provide them with the same.  Humidity levels should be kept high at around 65 to 70%.  They need to be misted on a daily basis and a water dish should be provided.

Substrate

Newspaper, indoor/outdoor carpeting, artificial grass, Reptibark or Aspen

Food Requirements

Iguanas are herbivores (plant eaters).  They require food high in calcium content such as Kale, Mustard Greens, Beet and Turnip Greens, Dandelions (herbicide and pesticide free) these should make up about 45 to 50% of their salad.  Other items that should be fed along with these are Romaine, Green Beans, Figs Raspberries Grapes and Kiwi.  There food should be dusted with a calcium supplement.

Iguana's salads should always be placed on a plate or in a bowl to avoid ingesting any of the substrate.

For your information
The number one killer of Iguana's is improper care.  Iguanas require high calcium content in there dies or they will become deformed and die from Metabolic Bone Disease hence the requirement of the UVA, UVB lighting requirement.