Horizons in general. You are the artist and photographer. You can play with your camera to get a slightly different view with changing where your horizon is in your photo. Horizons go hand in hand with the Rule of Thirds which we will cover in later challenges. Depending on where your horizon is, you guide your viewers to what you want to show off in your photo.
Show us 4 to 6 photos where there are a lot of horizontal lines not necessary horizons or you have at least one strong horizon line.
Show us at least two photos with multiple horizons. Yes, the horizons have to be straight.
The road, the railway bridge, horizontal lines and the horizon
A temple festival in our place, the steps to the temple. Horizontal lines
This photo is from the platform , there are a lot of horizontal lines.
A temple not far from our place
We had been to Pushkar in Rajasthan a few years ago.
Mukhamani 
Comments are welcome :)