Trekking in Nepal is one of the best experience tourists can experience.
According to Lonely Planet, Nepal is one of the top 5th trekking destinations in the world. Everest Base Camp Trail, Nepal, where you would experience superb trekking and may even see death very close from your eyes as well.
Below is from The 10 best treks in the world published by Lonely Planet itself.
Everest Base Camp, Nepal

Image by lampertron
Reaching a height of 5,545m (18,193ft) at Kala Pattar, this three-week trek is extremely popular with those who want to be able to say, ‘I’ve been to the base of the world’s highest mountain’. The difficult trek passes undeniably spectacular scenery and is trafficked by Sherpa people of the Solu Khumbu. The heights reached during this trek are literally dizzying until you acclimatise to the altitude, and the continuous cutting across valleys certainly has its ups and downs.