Rose window in the context of "Stained glass"

Beauty is commonly described as a feature of objects that makes them pleasurable to perceive. Such objects include landscapes, sunsets, humans and works of art. Beauty, art and taste are the main subjects of aesthetics, one of the fields of study within philosophy. As a positive aesthetic value, it is contrasted with ugliness as its negative counterpart.

One difficulty in understanding beauty is that it has both objective and subjective aspects: it is seen as a property of things but also as depending on the emotional response of observers. Because of its subjective side, beauty is said to be "in the eye of the beholder". It has been argued that the ability on the side of the subject needed to perceive and judge beauty, sometimes referred to as the "sense of taste", can be trained and that the verdicts of experts coincide in the long run. This suggests the standards of validity of judgments of beauty are intersubjective, i.e. dependent on a group of judges, rather than fully subjective or objective.

Stained glass refers to coloured glass as a material or art and architectural works created from it. Although it is traditionally made in flat panels and used as windows, the creations of modern stained glass artists also include three-dimensional structures and sculpture. Modern vernacular usage has often extended the term "stained glass" to include domestic lead light and objets d'art created from glasswork, for example in the famous lamps of Louis Comfort Tiffany.

As a material stained glass is glass that has been coloured by adding metallic salts during its manufacture. It may then be further decorated in various ways. The coloured glass may be crafted into a stained-glass window, say, in which small pieces of glass are arranged to form patterns or pictures, held together (traditionally) by strips of lead, called cames or calms, and supported by a rigid frame. Painted details and yellow-coloured silver stain are often used to enhance the design. The term stained glass is also applied to enamelled glass in which the colors have been painted onto the glass and then fused to the glass in a kiln.

A window is an opening in a wall, door, roof, or vehicle that allows the exchange of light and may also allow the passage of sound and sometimes air. Modern windows are usually glazed or covered in some other transparent or translucent material, a sash set in a frame in the opening; the sash and frame are also referred to as a window. Many glazed windows may be opened, to allow ventilation, or closed to exclude inclement weather. Windows may have a latch or similar mechanism to lock the window shut or to hold it open by various amounts.

Types include the eyebrow window, fixed windows, hexagonal windows, single-hung, and double-hung sash windows, horizontal sliding sash windows, casement windows, awning windows, hopper windows, tilt, and slide windows (often door-sized), tilt and turn windows, transom windows, sidelight windows, jalousie or louvered windows, clerestory windows, lancet windows, skylights, roof windows, roof lanterns, bay windows, oriel windows, thermal, or Diocletian, windows, picture windows, rose windows, emergency exit windows, stained glass windows, French windows, panel windows, double/triple-paned windows, and witch windows.

On 15 April 2019, at 18:18 CEST, a structural fire broke out in the roof space of Notre-Dame de Paris, a medieval Catholic cathedral in Paris, France, that is part of the "Paris, Banks of the Seine" UNESCO World Heritage Site.

The fire, which investigators believe was started by a cigarette or an electrical short circuit, destroyed the cathedral's wooden spire (flèche) and most of the wooden roof and severely damaged the cathedral's upper walls. The vaulted stone ceiling largely contained the burning roof as it collapsed, preventing extensive damage to the interior. Many works of art and religious relics were moved to safety, but others suffered smoke damage, and some of the exterior art was damaged or destroyed. The cathedral's altar, two pipe organs, and three 13th-century rose windows suffered little or no damage. Three emergency workers were injured. The fire contaminated the site and nearby areas of Paris with toxic dust and lead.

In theology, divine light (also called divine radiance or divine refulgence) is an aspect of divine presence perceived as light during a theophany or vision, or represented as such in allegory or metaphor.

Light has always been associated with a religious and philosophical symbolic meaning, considered a source of not only physical but metaphysical illumination, as a metaphor for the revelation of a truth hidden in the shadows.

A barrel vault, also known as a tunnel vault, wagon vault or wagonhead vault, is an architectural element formed by the extrusion of a single curve (or pair of curves, in the case of a pointed barrel vault) along a given distance. The curves are typically circular in shape, lending a semi-cylindrical appearance to the total design. The barrel vault is the simplest form of a vault: effectively a series of arches placed side by side (i.e., one after another). It is a form of barrel roof.

As with all arch-based constructions, there is an outward thrust generated against the walls underneath a barrel vault. There are several mechanisms for absorbing this thrust. One is to make the walls exceedingly thick and strong – this is a primitive and sometimes unacceptable method. A more elegant method is to build two or more vaults parallel to each other; the forces of their outward thrusts will thus negate each other. This method was most often used in construction of churches, where several vaulted naves ran parallel down the length of the building. However, the outer walls of the outermost vault would still have to be quite strong or reinforced by buttressing. The third and most elegant mechanism to resist the lateral thrust was to create an intersection of two barrel vaults at right angles, thus forming a groin vault.