Meditation was not invented by Buddha. Every way of spiritual development and every religion seems to include some phase of gathering or concentration. But meditations can differ. Their contents and techniques totally depend on the goal, that is to be achieved with their help.
The first goal in Buddhism is liberation from what disturbs us, like fears, outbreaks of disturbing emotions, confusion, and the like. To reach this goal, Buddha taught meditations which calm the mind (Tib.: Shinay or Skr.: Shamata). By concentrating on one's breath, on external objects like pictures or statues, or on imagined objects like forms of light or Buddhas, you can free yourself from experiencing thoughts and emotions as compulsive.

Concentrating on an object of meditation is a remedy, to stop the mind from wandering around. As soon as a distraction is noticed, concentration is refocused towards the object of meditation, but without thinking about its special features. The object of meditation only is a support for concentration.

The Great Way focuses on developing love and compassion, on one hand to accumulate many positive impressions in one's own mind, which brings forth pleasant experiences, and on the other hand, to overcome selfish attitudes. In the Diamondway the concentration phase is used to attune to the abilities of the fully developed mind. Qualities like joy, fearlessness, love and inspiration are imagined as forms of light and energy. In addition to concentration this also brings about identification with enlightened qualities.
The ultimate goal of Great Way Buddhism (Mahayana) is enlightenment - the total realization of all qualities of the mind. This means, feeling comfortable with every situation, experiencing boundless joy, free from external conditions, and bringing forth undiscriminating, very active love.

In order to reach this goal, you have to recognize, who experiences, what is behind the term "I", and what is experienced.
What reality do experiences and experienced objects have, and how are they related? This cognitive process through exchange with a teacher or during meditation is called Lhagtong (Tib.) or Vipashyana (Skr.). Beyond calm abiding, here, also all roots of disturbances are removed from the mind.

From deep insight into the nature of mind and of all things arises the full development of our inherent potential. In the Diamondway (Vajrayana) this is further supported by merging with the imagined Buddha form so that enlightened qualities can be experienced directly. At the end of the meditation, all positive impressions that were built up, are given away to all beings, so meditation will not nourish our ego.
What is special about Buddhist meditations, is not only their immense diversity and the power of their clearness, but  most of all their one-pointedness, completely focused on reaching liberation and enlightenment very fast.
Buddhist meditation does not have to be complicated or require long retreats: Even some few minutes of meditation every day can soon bring strong results.