Allah said: "I have prepared for My pious servants things which have never been seen by an eye, nor heard by an ear, or (even) imagined by a human being." (Sahih Muslim)
Jannat is a very large and very beautiful place. It has been made by Allah Ta'ala for Muslims. It's walls have been made of bricks of gold and silver and it's cement is made of musk. The ground is made of saffron and ambergris (a wax like substance). Instead of stones there will be diamonds and pearls. To house the residents of Jannat, there are mansions and large conservatories made of pearls, diamonds and beautiful jewellery. Each level is as large in breadth as the sky to the ground. It's doors are so wide that a fast horse would have to run seventy years to get from one side to another. There will be so many gifts in Jannat that you would not dream or think about. There will be different types of fruits, milk. honey, wine (sweet smelling non alcoholic) and other nice types of food. Jannatees will be given clothes so beautiful that no-one in this world will have ever had fate to wear. For assistance, thousands of clean, pure servants will be available and for company, beautiful "Hoorehs" (princesses) whose beauty will be so much that if one actually looked towards this world the people just by looking at her beauty and shining face would become unconscious. As for health, you will never sleep, nor will you ever become ill nor will anyone ever have a worry or nor will you ever die. There will never be any sort of difficulties, in fact there will be every type of rest and ever desire will be fulfilled. The biggest gift of all will be to see Allah Ta'ala.