Doors Open Ontario is returning this spring, giving people from all across the province the chance to explore some of the coolest corners of Ontario.

The annual event, thrown by the Ontario Heritage Trust, affords Ontario residents the chance to delve deeper into the past, present and future of the province by allowing exclusive access to some highly coveted spots.

This year's event kicks off in Guelph on April 27, before being held at various locations around the province throughout the spring, summer and fall.

During Doors Open Ontario, visitors will be able to explore historic and significant buildings, studios and sites usually restricted to the public while also being granted free admission to museums and attractions, making it one of the best reasons to set off on a weekend getaway.

Toronto will be participating in Doors Open Ontario on May 25 and 26, giving rare access to over 15o buildings and sites across the city, along with a number of museums and attractions for free.

Here's a complete list of all cities, towns and regions participating in Doors Open Ontario:

• Guelph — April 27
• Oshawa — May 4
• Hamilton Region — May 4-5
• Richmond Hill — May 11
• Toronto — May 25-26
• Ottawa — June 1-2
• Whitchurch-Stouffville — June 1
• Markham — June 8
• Loyalist Township — June 15
• Kingston and Area — July 20
• Burlington — August 10
• Cornwall and SDG Counties — August 17-18
• Owen Sound — August 24
• Belleville — September 7
• Carleton Place — September 14
• Peterborough — September 14
• Kawartha Lakes — September 15
• Waterloo Region — September 21
• London — September 21-22
• Mississippi Mills — September 22
• Brockton — September 28
• Lambton County — September 28-29
• Halton Hills — September 29
• Timmins — October 5
• Niagara-on-the-Lake — October 19
• Niagara Falls — October 26-27