Reading the works of foreign authors can give remarkable insight into other cultures and places. From details like different everyday customs to greater differences like outlook on life or religion, when books are written for other people and languages, you can learn even more if you are willing to open your mind.
Poetry is one of the most underrated types of reading. Poems really challenge the brain by engaging in symbolism, allegory, and unclear meanings. Pick up an anthology of poems and choose one poem per day. Spend some time on the poem, read it out loud, and let your brain wrap around the words, meanings, and intentions of the poet. Or just enjoy.