Which planet is about the same size as Earth?

Could you tell me, which celestial body orbiting our sun is roughly equivalent in size to our own blue planet, Earth? It's fascinating to consider the vastness of space and the potential for other worlds to harbor life, so I'm particularly intrigued by this comparison. Is it Venus, with its thick, suffocating atmosphere? Or perhaps Mars, the so-called "Red Planet," though it's notably smaller? I'm eager to learn the answer to this intriguing question.