Have a look at this picture of climbers waiting their turn to reach the summit of the tallest mountain in the world, Mount Everest.
Many experts are worried the climbers are putting themselves in danger as spending too much time at high altitude is extremely dangerous.
There is less oxygen at that altitude so your body has to work much harder to breathe.
It is advised people summit the mountain and head back down as soon as possible.
Ten people have died in the last week trying to tackle the 8,848-metre peak - more than the total for the whole of last year.
Nepal has issued a total of 381 permits costing $11,000 each (that's about £8,666) for the spring climbing season, which runs between March and May.