If you heard of pergolas, but still not quite sure what they are, let me offer a brief description. A pergola is a structure that creates a cool and shaded, pleasant area below. Support columns run along the sides, connecting to various types of lattice framework above. It is very common to leave the walls of open structure, while the top may be covered by a variety of plants or vines at the top.
Of course you can train your plants climb to the top of the garden structure, so choose things like roses, grapes, jasmine are the most appropriate. Climbing plants and vines are not a requirement however, and choose what you want your structure to look like will depend on your personal taste. Pergola professional builders often incorporate the structure into a trellis or arbor, providing further accents the garden. Your garden structure can be a simple feature in your garden, or could even be a more prepared to act as road or path, or designed as a corner pergola.