American Falls, Niagara Falls, Canada

This image is a view of the American Falls as seen from Queen Victoria Park on the Canadian side of the river.

F. H. Leslie, Limited, Niagara Falls, Ont.

There is no description on the back of the card, only the legend printed above the falls on the front.
The boat depicted is the famous Maid of the Mist tour boat, which was first used in ferry service before the American Civil War. It was relaunched as a tour boat service in 1895.
The image was originally black and white, then professionally colored. However, the pink ring on the image is a stain from a glass. The postcard was used and is dated 1957.
 

Maple Leaf Cabins, Niagara Falls, Canada

This image begins a series of cards featuring the world famous Niagara Falls, long a site for honeymooners and other vacationeers.

Johnson Press, Stamford Centre, Ontario

This is one of the old style cards that did not have any description listed on the back, just printed guide marks for postage, address and message. The signs visible on the front of the main office indicate that this was also something of a general store.
The address no longer exists, since the numbers for the street were changed sometime in the past, but the current business at this same location is still a tourist hotel.
The vehicles visible in the photo indicate that this image is from the 1940s.

Lake Okoboji Methodist Camp, Iowa

This image includes both of the main structures present at the Methodist Camp on Lake Okoboji during the 1940s. At right is the Tabernacle, which was a replacement for one built in 1915 and demolished by a tornado in 1926. In the distance is the Epworth Hall. The camp is used for Methodist families for summer recreation and religious studies.

The L.L. Cook Co., Milwaukee, WI

The Tabernacle was rebuilt in 1927 and finally demolished in 2012. The Epworth Hall, built in 1928, is still present on the site. This image dates from the 1940s.

Des Moines Beach, W. Okoboji Lake, Iowa

This image shows a couple of the private docks extending out from the Des Moines beach area of West Okoboji Lake. Tied up at the closer dock is an excellent example of a wooden pleasure boat from the 1940s.

The L.L. Cook Co., Milwaukee, WI

Docks such as these  were commonly built by owners of lakefront property as well as being built and operated by resort and campground owners. This picture dates from the 1940s.

Manhattan Beach, W. Okoboji Lake, Iowa

This is a view from the resort at Manhattan Beach, on the western shore of West Okoboji Lake in Iowa. The resort is still there, though much improved and expanded since this photo.

The L.L. Cook Co., Milwaukee, WI

In the background, on the lake itself, is a tourist boat common on the lake then and now. This image dates from the 1940s.

Lakes Minnewashta and W. Okoboji, Arnolds Park, Iowa

Returning to the air again for a different view of the resort town and amusement park at Arnolds Park, Iowa, we see a smaller lake in the foreground, the isthmus of land beyond it where Arnolds Park is situated, and then the larger lake across the background of the photo.

The L.L. Cook Co., Milwaukee, WI

Careful inspection of the image shows a notation on the near shoreline labelled “Oak Hill”. It is not clear what this signifies but it is in close proximity to a boat launch and pier, so it may be another public establishment.
This picture is clearly labeled as being from 1942.

Roof Garden Pavilion, Arnolds Park Amusement Park, IA

Moving down to water level and focusing on the shoreline reveals the large pavilion building called the Roof Garden, a public hall available then and now for larger gatherings.

The L.L. Cook Co., Milwaukee, WI

This building is now one of several facilities in place for events and performances as well as private rentals. The picture almost certainly dates from the 1940s.

Arnolds Park, Iowa

This aerial photo shows the town of Arnolds Park as it borders on W. Okoboji Lake in Iowa. The town is in the extreme northwest corner of Iowa, and is closer to many cities in Minnesota than in Iowa.

The L.L. Cook Co., Milwaukee, WI

This town forms much of the southeast shore of W. Okoboji Lake. This caption indicates this image was made in 1942.

West Okoboji Lake, Arnolds Park, Iowa

This picture was taken from a vantage point that would put it just off the right edge of the previous picture. The same objects are present in the foreground and background.

The L.L. Cook Co., Milwaukee, WI

In addition, the legend on the picture clearly states this is the Highway 71 route between the lakes, looking generally southwest. It is a habit of road constructors to put these barriers at the sides of bridges as they cross over water, but the difference in safety provided the barrier relative to the road immediately before and after is such as to make the barrier almost comical.
This card likely dates from the 1940s.