A drilling installation for drilling a well, for example an oil, a gas, or a thermal well, includes a tower structure, a first hoisting device adapted to manipulate a first object in a first firing line in the longitudinal direction of the tower structure, a second hoisting device adapted to manipulate a second object in a second firing line in the longitudinal direction of the tower structure, a storage device for vertically storing tubular elements, such as joined tubulars, and a first pipe racker for moving tubular elements between the storage device and the first firing line. The first and second firing line are located outside the tower structure.