A mountain is a landform that stretches above the surrounding land in a limited area usually in the form of a peak. A mountain is generally steeper than a hill. The adjective montane is used to describe mountainous areas and things associated with them.
There is no universally-accepted definition of mountain. Often, whether something is called a mountain depends on usage among the local people. One more objective definition is that mountains are land areas that are greater than 2,500m in height, or 1500-2499m if their slope is greater than 2 degrees, or 1000-1499m if their slope is greater than 5 degrees and local (radius 7km) elevation is greater than 300m, or 300-999m if their local (radius 7km) elevation is greater than 300m.
On the basis of this definition, mountains cover 64% of Asia, 25% of Europe, 22% of South America, 17% of Australia, and 3% of Africa. As a whole, 24% of the Earth's land mass is mountainous and 10% of people live in mountainous regions. Most of the world's rivers are fed from mountain sources, and more than half of humanity depends on mountains for water.
A number of mountains and mountain ranges of the world have been left in their natural state, and are today primarily used for recreation, while others are used for logging, mining, grazing, or see little use. Some mountains offer spectacular views from their summits, while others are densely wooded. Summit accessibility is affected by height, steepness, latitude, terrain, weather. Roads, lifts, or tramways affect accessibility. Hiking, backpacking, mountaineering, rock climbing, ice climbing, downhill skiing, and snowboarding are recreational activities enjoyed on mountains. Mountains that support heavy recreational use (especially downhill skiing) are often the locations of mountain resorts.
Mountains can be characterized in several ways. Some mountains are volcanoes and can be characterized by the type of lava. Other mountains are shaped by glacial processes and can be characterized by their glaciated features. Still others are typified by the faulting and folding of the Earth's crust, or by the collision of continental plates via plate tectonics (the Himalayas, for instance). Shape and placement within the overall landscape also define mountains and mountainous structures (such as butte and monadnock). Finally, mountains can be characterized by the type of rock that make up their composition.
Specific kind of mountains are so called table mounatins. These mountains were formed by sediments (mostly sandstone) as a plateau. Later this plateau was pushed up by tectonic forces and deeply dissected by water erosion.
Albatros Travel and Expeditions can provide you many trips directed into mountains and mountain ranges not higher than 4000 m. These trips are usually moderate or easy. Even not well trained people can take part in most of such journeys. There is a list of countries where such mountains can be visited:
Indonesia - important part of national parks of almost all islands
Sri Lanka - central and eastern parts
New Zealand - mountain ranges running through both islands from the north to the south
Chile - most of the territory
Ecuador - lower parts of Andean range in central parts of the country
Tanzania - mostly mountain ranges in west and southwest of the country