Rust
Systems language with memory safety without GC — Graydon Hoare at Mozilla, 2010, v1.0 in 2015. "Stop writing C++."
Ownership + borrow checker guarantee that the same memory isn't mutated by two threads at once. Algebraic data types (enum), pattern matching, traits, lifetimes. Cargo as package manager + build tool is industry-standard-great.
Powers parts of Firefox, Cloudflare Workers, Discord backend, AWS Firecracker, the Linux kernel (since 2022). Web frontend via WASM (Yew, Leptos). Hottest in blockchain (Solana, Polkadot). Most-loved language in the Stack Overflow survey 8 years running.