(CNN) — It would be a shame to visit Korea without clambering to the top -- or at least along the slope -- of one of the country's many, many mountains. Korea was blessed with a shapely topography: 70% of its landscape is mountain (the other 30%, expensive coffeeshops).
Around this time of year, due to the startling colors of the curvy landscape, the trails will doubtlessly be packed with streams of hikers in garishly colored hiking gear, sometimes smelling like soju.
But there are also many paths to the top of the mountain (literally), and many excellent paths that don't necessarily lead to the top.
Here's where to check out the most vibrant autumnal hues or, later in the year, the bleached landscape of a snowy mountaintop.
Seoraksan is not South Korea's tallest or prettiest mountain, but it is nonetheless one of the most beloved.
At 1,708 meters, Daecheongbong is Seoraksan's highest peak, and a favorite with novice mountaineers. Depending on where you begin your journey, the trek to the top can be done in as little as three hours. Lower down, the popular Cheonbuldong Valley explodes into a riot of color in fall. But the two-hour trek to the top of Ulsan Bawi (876 meters) can be particularly rewarding, not just for the physical exercise, but also the sensational views of the eastern sea, Daecheongbong and the valleys below.
According to the Korea Meteorological Administration, fall foliage on Seoraksan peaked on October 17 this year. The colors generally hold until late October, however.
Sinheungsa (신흥사); 170 Seorak-dong, Sokcho-si, Gangwon Province (강원도 속초시 설악동 170); +82 33 636 7700 (Seoraksan National Park Office)
From Baegundae you can see neighboring peak Insubong.
Seoul, amidst its urban sprawl, has seven mountains.
But the greatest of these is perhaps Bukhansan, sometimes called the "lungs of Seoul" for the role it plays in helping clear out the city's CO2.
The three-hour hike up to Baegundae, Seoul's highest peak (836 meters) beginning from the Bukhansanseong Hiking Support Center near Gupabal Station (subway line three), is one of the most popular trails.
And for good reason: steep enough to keep your feet busy, with a superb bird's-eye view of Seoul, it's still perfectly doable for even the casual weekend hiker.
The peak date for fall foliage is October 26.
Bukhansanseong Hiking Support Center (북한산성탐방지원센터); 62 Jingwang-dong, Eunpyeong-gu, Seoul (서울특별시 은평구 진관동 62); +82 357 9698 (Hiking Support Center); +82 2 909 0497 (Bukhansan National Park)
For the less religiously inclined, the stacked stones of Cheonjedan may not seem particularly impressive visually, but the "snow flowers" should more than make up for that.
Dangun, the legendary founder of Korea's ancient kingdom Goguryeo, was supposedly born on a mountain called Taebaeksan. On the 1,567-meter highest peak, Janggunbong, there's Cheonjedan, "altar for heavenly rites," where, in an earlier time, the devout would perform rites to honor the gods.
Taebaeksan really blooms in the winter when the branches sparkle with frozen snow. In Korean, the sight is literally referred to as "snow flowers."
Fall here is, however, are sadly underrated. While less monochromatically striking, autumn weather makes for good walking, and Taebaeksan's leaves are also a-changing.
Despite its height, the way up to Janggunbong is more of a gentle slope than a craggy scarp. Getting there should not take more than two hours from the Baekdansa (Baekdan Temple) entrance.
Baekdansa entrance to Taebaeksan; 57-2 Mungoksodo-dong, Taebaek-si, Gangwon Province (강원도 태백시 문곡소도동 57-2); +82 33 552 7187 (Baekdansa); +82 33 550 2741 (Taebaksan Provincial Park Office)
Songnisan means, "to leave mainstream society." Perhaps a bit exaggerated, but yes, we get it: it's beautiful.
The most important thing to know about Songnisan is that it's a damn good-looking mountain.
In autumn, the leaves die in varying shades of scarlet alongside the weird and wonderful rock formations that make up Songnisan's cliffs.
The highest peak is Cheonwangbong at 1,058 meters, but the loveliest is cloud-shrouded Munjangdae at 1,054 meters. The view from Munjangdae is also spectacular, and if you start at Shilla-era Buddhist temple Beopjusa, you can get there in three hours.
Tip: Beopjusa also has a Temple Stay program, if you'd like to "leave mainstream society" for a bit longer than an afternoon trek. It's also home to the peninsula's largest Buddha statue, 33 meters of wisdom incarnate covered in gold leaf.
The fall foliage peaks on October 26.
Beopjusa (법주사); 209 Sanae-ri, Songnisan-myeon, Boeun-gun, North Chungcheong Province (충청북도 보은군 속리산면 사내리 209); +82 43 542 5267 (Songnisan National Park)
Ever wonder where photographers for calendars of unrealistically pretty mountain vistas go for their material? You can't Photoshop this kind of stuff.
The granddaddy of Korea's mainland mountains, Jirisan is huge. The park that encompasses the mountain's many peaks is Korea's largest national park (484 square kilometers). The highest peak, Cheonwangbong (1,915 meters), is second only to Hallasan.
But one of the best places to really get into the spirit of autumn is in the valleys, such as the spectacularly beautiful Piagol Valley to the south. You can begin at Yeongok Hiking Support Center and walk the entire length (five hours), or linger in place to gawk.
The fall foliage peaked on October 18, but the valleys, which change later than the peaks, should still have some red left in them for a few weeks yet.
Yeongok Hiking Support Center; Naedong-ri, Toji-myeon, Gurye-gun, South Jeolla Province (전라남도 구례군 토지면 내동리); +82 55 972 7771 (Jirisan National Park Office)
Seasonal makeovers have a way of transforming your average mountain.
On its own merits, it might seem like Naejangsan doesn't really have a place on a representative list of South Korean mountains. Sinseonbong, at a measly 763 meters, is its highest peak.
But Naejangsan's yearly transformation is so radiant that it has been known has fall foliage central for approximately 500 years now.
The most commonly traversed course is the three-hour walk to peak Seoraebong from the Hiking Information Center, but the show starts before that.
On the walk from the Hiking Information Center to Buddhist temple Naejangsa you come across an avenue lined with 108 densely-packed trees, decked out in all manner of golds, oranges and reds.
All this fall foliage is due to peak on November 6.
59-10 Naejang-dong, Jeongeup-si, North Jeolla Province (전라북도 정읍시 내장동 59-10); +82 63 538 7875 (Naejangsan National Park office)
Up for climbing an volcano? Head to Hallasan.
Hallasan, a volcanic mountain that makes up most of Jeju Island as well as South Korea's tallest peak (1,950 meters), is also more of a winter player.
But that doesn't mean you can't appreciate its autumns (as well as the volcanic cones or lava flows that also decorate the landscape).
Many visitors start at Hallasan National Park's Visitors Center and make their way up along the Eorimok Trail, but this trail won't take you to the peak, where Baeknokdam, the crater lake at the top, awaits.
The Seongpanak Trail, which starts at Seongpanak, to the east, will take some patience -- five hours' worth -- to complete, but it takes you to the lake.
Fall foliage is due to peak on October 30.
San 137-24, Gyorae-ri, Jocheon-eup, Jeju-si, Jeju Province (제주특별자치도 제주시 조천읍 교래리 산137-24); +82 64 710 4073 (Seongpanak Ticket Office); +82 64 713 9950 (Hallasan National Park Office)