The top shows at this year's Contact Photography Festival mark its 19th anniversary. In the past two decades, the festival has grown into the largest photography event in the world.

With over 1,500 Canadian and international photographers exhibiting at more than 175 venues, Contact takes over the whole city, filling galleries and businesses and turning building facades and billboards into open-air galleries.

Here are my picks for the top shows at Contact 2015.

PRIMARY EXHIBITIONS
Primary exhibitions are large institutional exhibitions with an international reach curated by senior curators. These works are the cream of the crop of photography.

Mark Ruwedel & Scott Conarroe (Ryerson Image Centre, April 29 to June 28)
This collaboration with the Ryerson Image Centre showcases the landscape photography of Mark Ruwedel, the winner of the 2014 Scotiabank Photography Award. His haunting images feature traces of human activity, left like imprinted scars, on desolate landscapes from the western territories of the United States and Canada.

Part Picture (MOCCA, May 1-31)
This collaboration between curator, artists, and writer Chris Wiley and the Museum of Contemporary Canadian Art features the works of 13 artists who are reacting to the rise of the ubiquitous, dematerialized digital images. Their work borrows from painting and sculpture to create hybrid pieces that are only part photographs.

Watchers, Seekers, Keepers - Vanley Burke (BAND Gallery, April 30 to May 31)
Vanley Burke's iconic images of '70s and '80s black Britain at BAND strike as both timely and tragic in the time of movements such as #BlackLivesMatter: images of crowds gathering for African Liberation Day can't help but remind us of the streets Ferguson. This is a show about legacy, history, and African diaspora.

PUBLIC INSTALLATIONS
The public installations at Contact take photography out of galleries and bring it into the public domain - decorating billboards and building facades across the city.

Best Beach - Sarah Anne Johnson (Westin Harbour Castle, May 1-December 3)
At 140x40' Sarah Anne Johnson's "Best Beach" on the side of the Westin Harbour Castle, will be the largest mural in Toronto's history. The piece is a photographic composite of Toronto Island's south shore enhanced with colour digitally and by hand. Her work evokes how our feelings and experiences filter the way we see certain vistas.

Edouard - Edouard LeBouthillier (Union Station Vitrines at VIA Rail Concourse, May 1-31)
A must-see show for local history buffs, this exhibit is based on polaroids of '70s and '80s Toronto taken by amateur photographer Edouard LeBouthillier. The collection was found by the Archive of Modern Conflict Toronto in 2000 curbside in the Annex. Images are meticulously labeled with time, date, name and location.

Jihyun Jung - Demolition Site (MOCCA Courtyard & Alcove, April 24 - August 31)
Korean artist Jihyun Jung's installation of a demolition will be mounted in the MOCCA Courtyard just before the gallery is destroyed to make room for new condos. Jung's large-scale mural depicts a dismantled apartment, speaking to the violence and carnage of urban development.

Flat Death - Sara Cwynar (Billboards on Lansdowne Ave, May 1 - 31)
These public installations will number among the easiest to catch (Lansdowne at Dundas West and College) for west enders. Represented by Cooper Cole, Cwyar's Encyclopedia of Kitsch is one of my favourite possessions, and these large scale photographs of 3D collages will continue her search for meaning in outmoded ephemera. AJ

FEATURED EXHIBITIONS
These exhibitions take place in large galleries across the city and represent juried selections of some of the best works from around the world.

Looking for Marshall McLuhan in Afghanistan - Rita Leistner (Dylan Ellis Gallery, April 15 - May 13)
Rita Leistner works with master printer Bob Carnie to create these painterly three-colour prints of photographs taken on an iPhone and edited with the Hipstamatic app during a military embed in Afghanistan. The images speak to the tension between high-tech and low-tech in both photography and warfare.

OPEN EXHIBITIONS
These non-juried exhibitions are extremely important to Contact's community building efforts and speak to the festival's commitment to keep connected to its grass roots history. They can be hit or miss, but they're worth the risk.

Toronto System - Shawn Micallef (Coolearth Architecture inc, May 1 - 31)
Known mostly as a writer, Shawn Micallef may be best described as a biographer of Toronto. His photography explores the city from the expert vantage point of someone who knows our streets like the back of his hand.

Photographing the World, One Torontonian at a Time - Colin Boyd Shafer (Daniels Spectrum, May 1 - June 28)
This exhibit is akin to the popular Humans of New York project, chronicling the photos as well as personal stories of the people featured. What sets Colin Boyd Shafer's project apart is his focus on the stories and images of immigrants living in Toronto.

BONUS

Sally Mann In Conversation with Paul Roth (Ryerson University - May 22)
As part of Contact's Public Programs, acclaimed American photographer and Guggenheim Foundation Fellowship winner Sally Mann will discuss her new memoir Hold Still, a personal history that reads like a novel. Bonus: go home with a free, signed copy of her book.

What Contact shows are you hoping to catch this year? Share your suggestions in the comments below.

Images: Lucas Blalock, Same Kinds of Arguments, 2014, Courtesy of the Artist and Ramiken Crucible, New York; Vanley Burke, Siffa Sound System, Handsworth Park, 1983, Courtesy of the artist; Sarah Anne Johnson, Best Beach (detail), 2015, Courtesy of Stephen Bulger Gallery, Toronto and Julie Saul Gallery, New York; Image courtesy of Archive of Modern Conflict Toronto; Michael Barker, Untitled (from the series The Lab), 2013; Scott Conarroe, Works Yard; Colin Boyd Shafer, Melvyn (Born in Botswana) holding a photograph of his late brother, 2014; Sara Cwynar, Contemporary Floral Arrangement 5 (A Compact Mass), 2014, Courtesy of the artist and Cooper Cole Gallery; Sara Cwynar, Man and Space (Books 2), 2013, Courtesy of the artist and Cooper Cole Gallery

With contributions by Aubrey Jax.

Follow Sima Sahar Zerehi on Twitter @SimaSaharZerehi