The Royal Ontario Museum, commonly known as the ROM (rhyming with Mom), is a major museum for world culture and natural history in the city of Toronto, Ontario, Canada. The ROM is the fifth largest museum in North America and contains more than six million items and over 40 galleries. It is also the largest museum in Canada. It has notable collections of dinosaurs, Near Eastern and African art, East Asian art, European history, and Canadian history.
The museum is located at the corner of Bloor Street and Avenue Road, north of Queen's Park and on the east side of Philosopher's Walk in the University of Toronto. Established in 1912 by the provincial government, the Royal Ontario Museum was operated by the University of Toronto until 1968. Now an independent institution, the museum still maintains close relations with the university, often sharing expertise and resources.

Building
The ROM's first expansion saw the construction of the wing fronting onto Queen's Park. Opened on October 12, 1933, it included the museum's elaborate art deco, Byzantine-inspired rotunda and a new main entrance. To employ as many men as possible during the Great Depression, the excavation for the basements and foundations were undertaken by hand, with teams of workers working alternate weeks. The new wing was designed by Alfred H. Chapman and James Oxley, and required the demolition of Argyle House, a Victorian mansion at 100 Queen's Park.
The linking wing and rear (west) facade of the Queen's Park wing were originally done in the same yellow brick as the 1914 building, with minor Italianate detailing. However, the Queen's Park facade of the expansion broke from the heavy Italianate style of the original structure. It was built in a neo-Byzantine style with rusticated stone, triple windows contained within recessed arches, and different-coloured stone arranged into a variety of patterns. This development from the Roman-inspired Italianate to a Byzantine influenced style reflected the historical development of Byzantine architecture from Roman architecture. Common among neo-Byzantine buildings in North America, the facade also contains elements of Gothic Revival in its relief carvings, gargoyles and statues. The ornate ceiling of the rotunda is covered predominantly in gold back-painted glass mosaic tiles, with coloured mosaic geometric patterns and images of real and mythical animals.
Writing in the Journal of the Royal Architectural Institute of Canada in 1933, A. S. Mathers said of the expansion: "The interior of the building is a surprise and a pleasant one; the somewhat complicated ornament of the facade is forgotten and a plan on the grand manner unfolds itself. It is simple, direct and big in scale. One is convinced that the early Beaux Arts training of the designer has not been in vain. The outstanding feature of the interior is the glass mosaic ceiling of the entrance rotunda. It is executed in colours and gold, and strikes a fine note in the one part of the building which the architect could decorate without conflicting with the exhibits."

First expansion
The second major addition was the Queen Elizabeth II Terrace Galleries on the north side of the building, and a curatorial centre built on the south, which were started in 1978, completed in 1984, and designed by Toronto architect Gene Kinoshita, with Mathers & Haldenby.
The new construction meant that a former outdoor "Chinese Garden" to the north of the building facing Bloor, along with an adjoining indoor restaurant, had to be dismantled.
In 1964, the McLaughlin Planetarium was added to the south, and a multi-level atrium was added in 1975, doubling the floor space. The planetarium was closed in 1995, then re-opened temporarily in 1998 as the Children's Own Museum. It is now used primarily as office space and storage.
Opened in 1984 by Elizabeth II, Queen of Canada, a $55 million expansion was built in a simple modernist style of poured concrete, glass, and pre-cast concrete and aggregate panels. It took the form of layered volumes, each rising layer stepping back from Bloor Street, hence creating a layered terrace effect. Though the design of this expansion won a Governor General's Award in Architecture, this last set of galleries was torn down in 2004 in favour of a new expansion designed by architect Daniel Libeskind.

Second expansion
The museum is currently undergoing a major renovation and expansion project, dubbed Renaissance ROM. The centrepiece is the recently-opened Michael Lee-Chin Crystal, designed by architect Daniel Libeskind and Bregman + Hamann Architects; installation of exhibits in the addition will continue over a period of months. Existing galleries and buildings are also being restored. Renovated galleries in the historic buildings will reopen in stages, and all work is scheduled to be completed by 2010.
Installation of the permanent galleries of the Lee-Chin Crystal began mid-June 2007, after a ten-day period when all the empty gallery spaces were open to the public. The completed galleries will open through winter 2007/08 and spring 2008 (see below).

Third Expansion
Originally, there were five major galleries at the ROM, one each for the fields of archeology, geology, mineralogy, paleontology, and zoology. In general the museum pieces were labeled and arranged in a static fashion that had changed little since Edwardian times. For example, the insects exhibit that lasted up until the 1970s housed insects from around the world in long rows of glass cases, with insects of the same genus pinned to the inside of the cabinet, with only the species name and location found as a description.
By the 1960s more interpretive displays were ushered in, among the first being the original dinosaur gallery, established in the mid-1960s. Dinosaur fossils were now staged in dynamic poses against backdrop paintings and models of contemporaneous landscapes and vegetation. The displays became more descriptive and interpretive, sometimes, as with the extinction of the woolly mammoth, offering several different leading theories on the issue for the visitor to ponder.
This trend continued, and up until the present time the galleries became less staid, and more dynamic or descriptive and interpretive. This trend arguably came to a culmination in the 1980s with the opening of The Bat Cave, where a sound system, strobe lights and gentle puffs of air attempts to re-create the experience of walking through a cave as a flock of bats fly out.
The original galleries were simply named after their subject material, but in more recent years, individual galleries have been named in honour of sponsors who have donated significant funds or collections to the institution. There are now main categories of galleries present in the ROM: the Natural History Galleries and the World Culture Galleries.

Galleries
The Natural history galleries are all collected on the second floor of the museum, and contains collections and samples of various animals from around the world.
The Gallery of Birds depicts several hundred bird specimens, illustrating the many different habits and ecological niches they inhabit. This gallery is dominated by the large "Birds in flight" display, and includes exhibits of now extinct species, such as the Passenger Pigeon.
The Bat Cave, a reconstruction of the St. Clair cave in Jamaica, is filled with bats and other animals typically found in such caves, including spiders and snakes.
The Hands-on Biodiversity Gallery provides visitors with the chance to experience and examine the world of nature close-up. Visit a glassed-in working beehive, examine shed snake skins, and look at drawers filled with insect, bird, amphibian, reptile and mammal specimens.
A wide range of snakes, lizards, crocodiles and turtles are represented in the Gallery of Reptiles.

Forthcoming galleries

It has been alleged on more than a few occasions that the Royal Ontario Museum is haunted by the ghost of its first curator, Charles Trick Currelly. The spirit has been reportedly seen in a nightshirt wandering in the Bishop White Gallery of Chinese Temple Art.
The Royal Ontario Museum runs its own children's camps for the summer, March Break, and Saturday mornings. It is widely renowned, and is recognized as being one of the best children's camps in the city of Toronto.
The glass in the new structure was reduced when it was realized that high light levels would be detrimental to the showcased pieces.
As the building envelope in the original structures was not designed to maintain the humidity levels needed for the safe exhibition of sensitive artefacts, the museum has championed the use of active microclimate control. This not only provides safe exhibit conditions, but also dramatically saves on the costs of air conditioning. Specialized microclimate control units are located throughout the old and new buildings to supply a gentle flow of filtered and humidity conditioned air to most of the display cases in the museum.